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. OCS Study

·i\U,fS9S:lio25"·

Monitoring Seabird Populations in Areas or Oil .

and Gas oevtopment on the Alaskan Continental Shelr:

MONIT([)RING POPULATIONS

AND I

PRODU<CTIVITY OF SEABIRDS

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AT COLONIES IN LOWER COOK INLET, ALASKA,

IN 1993 AND 1994

FINAL

REPORT

U& F18H.WILDLIFE

~"" T~'

Leslie Slater, G. Vernon Byrd, Jay W. Nelson, and John Ingrum

U.S. Fish and IWildIife Service .

Alaska Maritime National Wildlire Refuge . Homer, ,Alask!. . .
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. OCS Stud)·

MMS 95-0025

MONITORING POP I ATIONS AND PRODUCTIVITY OF SEABIRDS AT COLONIES IN LOWER

COOK INLET, ALASKA, IN 1993 AND 1994

... By

!Leslie Slater. G. Vernon Byrd. Jay W. Nelson and John·Ingrum .

U.S. Fish and Wildlife Service

. Alaska Maritime National Wildlife Refuge

2355 Kachemak Bay Drive. Suite lOi

Homer. Alaska 99603

This study was funded in part by:

·U.S...Department of Interior

Minerals Management Service

Environmental Studies Section

949 East 36th Avenue

Anchorage. Alaska 99510

As part of the

MMS Alaska Environmental Studies Program

May 1995

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The opinions, findings, conclusions, or recommendations expressed in Ihis report are those of the authors and

do not necessarily reflect the views of the Minerals Management Servi~e, nor does mention of trade names or

commercial productsconsti!Ute endorsement or recommendation for use by the Federal Government. , .

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PROJECT ORGANIZATION

Authors

Leslie Slater, senior author .

OVerall!responsibility for field work, supervised seasonal employees, helped COlleC'[ data,

drafted repon .

G. Vernon Byrd] coauthor

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Assisted with project planning, helped collect data, edited the repon

I Jay W, Nelson, coauthor

Field c.L~ leader at Chisik and Duck islands

I John Ingrum, coauthor

Field asLtant at Chisik and Duck islands

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Other Key Project Personnel

Joel Hubbard

Contract Officer's Technical Representative

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David Irons, FVvlS liaison with MMS

coordinkted with Minerals Management Service . I ..

John L. Man!n, Refuge Manager, Alaska Maritime NWR

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Provided overall supervision for the project

Christina Montot, Office Automation Clerk, Alaska Maritime NWR . I

Produceti the final repon on a word processor

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ExEcUTIvE SUMMARY

As pan of the Minerals Management Service's program to monitor seabird populations in areas of oil and gas

development on the Alask:+ continental shelf, surveys were made of breeding seabirds at colonies in lower

Cook Inlet, Alaska, in 1993 and 1994. Survey effons were devoted to all of the most common species

including cormorants, kitti~akes, gulls, murres, and puffins. The primary study, areas were Chisik and Duck

islands near Tuxedm Bay, rUIl Island and 60-foot Rock in Kachemak Bay, and Flat Islands near English Bay.

The objectives of the surveys in 1993 and 1994 were to assess population levels and reproductive success of

key species. Funhe'rmore jbOmparisons were made with past data to assess trends. The 1993 study was mOre

intensive and extensive than the 1994 surveys. .

During the 1993 and 1994!breeding seasons, kittiwakes appeared to initiatenesting within the normal range of

dates, but murres nt!'y havf been slightly late. Most species of seabirds had relatively low rates of productivity

in 1993 at Chisik arid Ducf Islands. Kittiwakes also failed at 60-foot Rock, and cormorant productivity was

below normal. ReproductIve success for kittiwakes at Gull Island was only slightly higher than a~ 60-foot Rock

in 1993. In contrasl, tufteCl pufrms seemed to produce well at Flat Islands in 1993. In 1994, it appeared that

, reproduCtive success was tietter for kittiwakes al Chisik and Gull islands than il had been in 1993. !n contrast,

kittiwakes failed to producb young al 60-fool ROck in 1994. ' ,

Double-crested cormoranJ apparently have decli~ed since th: early 19'70s at Chisik Island. but there was no

indication of a decli'ne in pelagic cormorants at Chisik and Duck or on the islands in Kachemak Bay. Glaucouswinged gulls increaSed or temained slable betw'een the mid-1970s and the early 1990s at all colonies.

Black-legged kittiw!.ke poJu:lalion trends varied among colonies. Apparently a slighl decline occurred since the

1970s at Chisik and Duck!lslands, bUI at Gull Island and 50-fOOl Rock the populations increased between the

mid-1970s and themid-1980s, slabilizing thereafter. . '

Common murres declined ai Chisik and Duck Islands between 1970 and the mid-1980s, but the populations have

remained slable since then..In contrast, numbers on Gull Island have increased since the mid-1970s. The , '

populalion of murres on 60-foot Rock contained few if any breeders in 1993 and 1994, and the number of birds

using the rock was 'lower lhan in the 1970s. '

There were too fe,,: hiS10lc~ data to assess changes in populationsof pigeon guillemots or tufted puffins.

Funhermore, techn,iques liave noi yet been developed to assess populationlevels of horned puffins.

Over the past 20 years, itlappears conditions have worsened for seabirds at Chisik and Duck islands whiie they

have improved at Gull Island. In contrast, 60-foot Rock is a small, unstable colony. We could not judge trends

at Flat Islands, but1they chirently have a substantial population of tufted puffins.

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T~d: of CONTENTS

, EXECUTIVE SUMl\1ARY """", , , .. , ..... ,.,

TABLE OF CONTENTS , , , .. , ".,.,., .. ".,.,.,.,. , .. , ,

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LIST OF TABLES' , ... , .... , .. , .. ' , .. , , , .. , .. , .. , , , , .. , .... , . . vii

• LIST OF FIGURES, .. 1.' ,.. , ,.. , ,.,'.. '.,' '.,.. ,.,.'.,viii I '" '

LIST OF APPENDICES , , .. , , ' .. ' .. , , . , ' , ix

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ABSTRACT ., .. ".' . ' , , , . , , , ..' , . ' , .. , , , . , , .. , ,

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INTRODUCTION , . : . , , .. , .. , , ' .. , .. , . , ' , . , " 2

STUDY AREAS ., ' , .. , , , , , .. , . , , .. , , , , .. , . 2

Chisik & Duck Iflands , , . , , , . , , , .. , . , , , , .. , , 2

Gull Island & 6O-loot Rock, .. , ., , , ' .. , . , , . , , . , , ' . , , .' 4

Flat Islands , , . , .. , , . , , .. , .. , .. , , . , , .. " 7

METHODS ;.. , , , .. , .. , , .. , , , .. , .. , . , , .. , . ' . , , , . , ., 7

Population Counts' , , , ', . . . . . . . . . . . . . . . . . . • . . . . . . . . . .. 7

Phenology "",."."".", , ,., , , .. ,.,. 9

Productiv\ty .,.: , ,.,." , .. " , ,... 9

Chick Growth & Diet , , , .. " .. ,.,., .. , , ,. 10

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RESULTS & DISCUSSI0N , . , .. , , .. , . , .. ' . , . ' , , . , , . , 10,

Chisik and Duck! Islands . , .. , .. , , . , .. , , . ' .. ' .. , . , , , , . , , . . . . 10

, I I:!ouble-1crested Connorant . ' . , . , .. , .. , . ' , , .. , . , , " ' ' 10

~elagic Connorant . , , , .. , . ' , .. , . , , ' . : , . , , . . 12

Glaucous-winged Gull , , .. , , , , .. , .. , . , , . , , 12

Black-IJgged Kittiwake .. , , . , ' . , .. , , . , , .. , , . 14 , I Common' Murre .. , . , , , , .. ' , , . , . ' , . , ' .. , . ' . , ' . , . . 19

Pigeon ,Guillemot, , , . , .. , , ' .. , , . , . , , .. , . .. 22

Homed Puffm ,. , , , .. " , , , . . 22

Gull , , I Island , , , , . ' , , .. , .. , , .. , , . 25

Pelagic!Connorant , .. , , . , . , .. , . ' , . ' , .. , .... , , . , . , , , 25

'Glaucous-winged Gull , , " ' .. , .. , . ' .. , ' ' . 29

Black-lfgged Kittiwake , , .. , , .. , . , , .. ', .. , , , . , , .. , 29

Common Murre , , , , .. ' ' . , .. , , . , 29

PigeonIGUillemot~ , , , , , .. , , , . , .' .. 33

6O-foot Rock: . , , , , '. , , , .. , . ,,, . , .. , , . , 33

, Doubld..crested Connorant , , ., , , , , . . 33

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' eI . aglc,Ie"onnorant .. , , , , , , . , , '33, .

Glauco,u~-wiDged , I ' Gull : . , . , . , , , .. , , . , , .. " 33

Black-legged Kittiwake .. .' , , .. , : , , 35'

Commori Murre , ' , .. , , . , . . 35

Pigeo~ Guillemot .",." ,., ,., ,." , ,.......... 35

Flat Islands . , .. , .. , .. ' , . , . , , , , , . , .. , . ' . , ' .. . 35

,Tufted Puffin , .. ' .. , ' , .. ' , . , .. , . , , .. , . , . , , , , . 37 ..

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CONCLUSIONS , _ , . 37

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ACKNOWLEDGEMENTS , , , .. , .. , ',' , 38

LITERATURE CITED , . , , 38

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liST OF TABLES

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1. Summary of double-crested, pelagic, and red-faced cormorant populallon

estimates o~ Plotsl in lower Cook Inlet colomes 11

2. Summary of pelagic cormorant productiVltyon Gull Island plots, 1988-1994 13

3. Summary of glaJous-Winged gull population estimates on plots in lower

Cook Inlet :coloni~s 15

4. Summary of blaoJ-jegged kittiwake population plot counts. at lower Cook

Inlet colonjes. . I '- .' . 17

5. Summary of nestmg phenology of black-legged kittiwakes at lower Cook -

Inlet colonies' I' . . 18

6. Sunimary of black-legged kittiwake productivity on plots at lower Cook

Inlet col0I1,1es I. . 20

7. Summary of common murre population plot counts for lower Cook Inlet

colonies: 1

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8. Breeding phenology of homed puffins at Duck Island, lower Cook Inlet,

Alaska: I

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9. Summary of homed puffm productivity at Duck Island, lower Cook Inlet,

:~::~son of 1e relatIve imponance of different fish species in bill'

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10.

I loads of homed puffins at Hall Island, 1976, and Duck Island, 1993 . 30

11. Pll I . 'geon gUl emot counts at lower Cook Inlet colomes 34

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LIST OF FIGURES

Study locations in lower Cook Inlet, Alaska

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Nesting distributions of black-legged kittiwakes and common murres,

and plot locationk on Chisik and Duck Islands, lower Cook Inlet, Alaska

Seabird ~onilOrilg plot locations on Gull Island and 6O-foot Rock;

Kachemak Bay, Naska

Tufted puffin nelting distribution on Flat Islands, Kachemak Bay,

Alaska: I

Population trends of black-legged kittiwakes based on whole-island

counts at Chisik Island, lower Cook Inlet, 1970-1994

,. Common murre population trends based on whole island counts at

Chisikand Duck Islands, Alaska

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Mass chahges of horned puffin chicks at Duck Island, lower Cook

Inlet, Alaska, iJ 1993' .

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Population trends of pelagic cormorants on plots at Gull Island,

lower Cook Inldt, 1986-1994 . I. .'

Population trends of black-legged kittiwakes on plots at Gull Island,

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lower Cook Inlet, 1986-1994

I . Population trends of common murres on plots at Gull Island, lower Cook Inlet, 1986-1994 I . . Population trends of black-Ieggedkitti';"akes on plots at 6O-foot Rock, I .

lower Cook Inlet, 1975-1994 .

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LIST OF APPENDICES .

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Summary of double-crested. pelagic, and red-faced cormorant population

estimates in selectbd lower Cook Inlet colonies , .

,Summary ~f gl:ulous-Winged gull population estimates in selected lower

Cook Inletcolonih

Summary (;f blacLegged kittiwake population estimates in selected lower , I

Cook InieLcolonies

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Summary of common murre populatton eSllmates for lower Cook Inlet

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Common murre producllvtty at Duck Island, Alaska, in 1993

., 1 " ' Diet samples brought to homed puffm chicks at Duck Island, Alaska,

'in1993 , I.

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Wildlife 'r~corde9 during a circumnavigation ofFlat Islands. Kachemak

Bay, Alaska. I July 1993

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ABSTRACT

In 1993 and 1994, we monitored the status of seabirds at major breeding colonies in lower Cook Inlet. Alaska.

a region in which the U.S! Minerals Management Service (MMS) is considering offering new leases for oil

development. The objeCtii~e of the monitoring program was to collect information on p~pulation trends and

patterns of reproductlve success for selected spec.es for assessment of potenualtmpacts of the MMS leasing

program. . I' , - Survey effons were devoted primarily to cormorants, kittiwakes, murres, and puffins. Information was also , gathered on gulls and guillemots. The primary study sites were Chisik and Duck Islands near Tuxedni Bay, the

largest and most diverse shbird colonies in the area, at Gull Island and 60-foot Rock in Kachemak Bav, and at j' . •

Flat Islands near Port Graham.

Our surveys and historicJ data that we reviewed provided a basis for eValuating changes in populations since

the mid-1970s in some c,.!;es, and since the mid-1980s in most cases.

At Chisik and Duck ISlanhs, the northernmost colonies in our survey of lower Cook Inlet, the predominant

breeding species of seabitds have either declined or remained stable since the early 1970s. DOUble-crested

cormorants, and commonlmurres appear to have declined most. Black-legged kittiwakes may have declined

slightly, and homed puffins also may have declined. There is no evidence of change for pelagic cormorants and

glaucous-winged gulls. I . " ' ,

At Gull Island, a different pattern was observed. Glaucous-winged gulls, black-legged kittiwakes. and common

murres have increaSed be\ween the mid-1970s and the early 1990s. Pelagic cormorants appear to have remained

unchanged over the perioli.

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Patterns of change at 60-foot Rock are less clear. At this small colony, counts of pelagic cormorants have been , , highly variable with no obvious pattern since the mid-1970s. Glaucous-winged gulls may have increased

between the mid-1970s ahd mid-1980s and remained stable since. A similar increase apparently occurred for

black-legged kittiwakes b~tween 1976 and 1990, but numbers had declined by 1993 and 1994 to mid-1980s

levels. Common 'murresIhave declined since the mid-1970s, but the colony is currently composed primarily of

roosting, non-breeding birds, therefore it is difficult to assess trends because of high VarIability in attendance

patterns. I

The primary seabird nesting at Flat Islands is tufted puffin. We found approximately 500 nest burrows in 1993,

but there were no ,historib data for comparison.

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During the 1993 and 1994 breeding seasons, kittiwakes appeared to initiate nesting within the normal range of

dates, but murres may h~ve been slightly late. Most species of seabirds had relatively low rates of productivity

in 1993 at Chisik 'and Dl.ck Islands. Kittiwakes apparently had a nearly total breeding failure. Kittiwakes also

failed at 60-foot Rock, arid cormorant productivity was below normal there as well. Reproductive success for

'kittiwakes at Gull Island!was also low, but they did not totally fail there in 1993. In contrast, puffins seemed to

produce well at Flat Islands. In 1994, we had fewer data, but it appeared to be a better year at Chisik and '

Duck Islands than in 1993. In addition, black-legged kittiwakes had moderately good success at Gull Island in

1994, but they failed at 60-foot Rock as they had in 1993.. '

The only thing we Ieamld about prey was that in 1993 homed puffins fed chicks mainly sand lance. The chicks

grew at relatively norrrnlJ rates so the amount of prey available during the chick-rearing phase must have been,

adequate. ' '
Overall. it appears that conditions over the past 20 years may have worsened for seabirds at Chisik and Duck

Islands while they have improved at Gull Island. Both remain substantial breeding colonies for seabirds. In

contrast, 60-foot Rock is a small, possibly unstable colony. We have no' basis for judging trends at Flat Islands.

where the primary species of nesting seabird is tufted puffm.

INTRODUCTION

Seabird colonies in lower Cook Inlet include predominantly pelagic cormorant (Phalacrocorax pelagicus),

double-crested cormorant (P. auritus), glaucous-winged gull (Larus glaucescens), black-legged kittiwake (Rissa

tridactyla), common murre (Uria aalge), pigeon guillemot (Cepphus columba), horned puffm (Fratercula

comiculata) and tufted puffin (F. cirrhata) (Sowls et al. 1978). These seabird populations are vulnerable to

environmental disturbance and pollution that.could possibly result from activities associated with oil and gas

exploration and production (Snarski 1974). In light of this planned indUStrial activity, the Minerals Management

Service (MMS) provided funding to the Alaska Maritime National Wildlife Refuge (AMNWR) to collect

baseline information on the population size and reproductive performance of the most common species in the

large"t seabird colonies in lower Cook Inlet in 1993 and 1994. Monitoring studies enable biologists to evaluate

the health of seabird populations and these studies provide a basis for assessing the effects of oil spills. Oil

from the TIV Exxon Valdez spill did not surround colonies in lower Cook Inlet.

The primary objective of this project was to assemble past data and characterize the current status of seabirds at

Chisik, Duck, Flat, and Gull Islands, and 60-foot Rock (Fig. I).

The largest colonies of nesting black-legged kittiwakes, common murres, and horned puffms in Cook Inlet occur

at Chisik and Duck Islands (Jones and Petersen 1979). Population estimates of kittiwakes were made on these

islands in the early I970s (Snarski 1970, 1971 a-c, 1974). Jones and Petersen (1979) investigated the breeding

succe:;s of black-legged kittiwakes, and reproduction and feeding habits of horned puffins in 1978 and 1979.

Biologists of the AMNWR have monitored populations and reproductive 'success of kittiwakes and murres

internnttently throughout the 1980s (Jones et al. 1980, Kafka 1984, MuhIberg 1984, Beringer and Nishimoto

1988). Smaller colonies of common murres and black-legged kittiwakes have been monitored on Gull Island

and 60-foot Rock by private consultants and government biologists perioqically since 1976 (Erikson 1976,

Nishimoto et al. 1987, Nishimoto and Beringer 1989, 1990) while little information on·seabirds is available

from Flat Islands (Sowls et al.1978). .

STUDY AREAS

Chisil~ & Duck Islands

Chisik and Duck Islands (hereinafter referred to as Chisik Island unless otherwise noted) are located on the

weste:cn side of lower Cook Inlet (60' 09'N,I52' 34'W, Fig. I), and are pan of the Alaska Maritime National

WildlLfe Refuge. Chisik Island is approximately 10.5 by 3.6 km in size, encompasses about 2606 ha, has a

peak elevation of 815 m, and is located about 0.8 km from the mainland. Duck Island is 0.4 km east of Chisik,

cover:; about 2.4 ha and reaches a maximum elevation of 49 m.

The vegetation on both islands is donrinated by dense alder (Alnus crispa) thickets with an understory containing

devi]" club (Oplopanox horridus), salmonberry (Rubus spectabilis), elderberry (Sambucus racemosa), nettles

(Uni,a Lyallii). ·and several representatives of the Umbelliferae.

The i!,lands are composed mainly of sedimentary materials such as sandstone, conglomerate, siltstone, and shale

formations; surface layers are compacted fallout from volcanic eruptions of Mounts Redoubt and Iliamna (Mark

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~~Barren Islands

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Figure 1. Study locatibns in lower Cook Inlet, Alaska

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Clark, Soil Conserv. Serv., pers. comm.). Substrate configuration results in continuous surface erosion and

unsafe climbing conditions.

In tbe recent past the islands have supponed breeding seabirds at the following approximate population levels:

double-crested connorant: 150 birds

pelagic connorant: 25-30 birds

glaucous-winged gull: 1000 birds

black-legged kittiwake: 18,000-20,000 birds

common murre: 3000-5000 birds

pigeonguillemot: 13 birds (on Fossil Point near Chisik)

homed puffin: 5000

tufted puffin: 1000

Kittiwakes nest primarily along cliffs located on the southwest side of Chisik Island, extending to the southern

tip (Fig. 2). Smaller numbers of kittiwakes and the majority of murres have historically nested along the central

ponion of the eastern coast. Murres also nest at suitable ledges along the entire perimeter of Duck Island, and

hom:d puffins nest in crevices found over much of Duck Island, .

Gull Island & 60-foot Rock

Gull Island, owned by the Seldovia Native Corporation, is about five km southeast of the tip of the Homer Spit

(59' 35' IO"N, 151 0 19' 45"W), and 60-foot Rock, pan of the Alaska Maritime National Wildlife Refuge, lies

about six km south of the Spit (59 0

33'N, 151' 28'W) (Fig. I). Both islands erupt sharply from the water and

are composed primarily of fractured bedrock. Gull Island has three ponions which are rarely connected at low

tide (Fig. 3). Herbaceous and some woody vegetation grows on the plateau area of Gull Island while 60-foot

Rock is mostly unvegetated.

Recent population estimates for seabirds occupying these islands follows:

Gull Island

pelagic cormorant: 250-300 birds

red-faced cormorant: 30-60 birds

glaucous-winged gull: 700-800 birds

black-legged kittiwake: 7000-8000 birds

common murre: 5000 birds

pigeon guillemot: 12-15 birds

homed puffin: 10

tufted pufrto: 500

60-foot Rock

pelagic cormorant: 30-50 birds

glaucous-winged gull: 80-100 birds

black;legged kittiwake: 300-400 birds

common murre: 150-230 birds

pigeon guillemot: 2 birds

tufted puffto: 50 birds

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M-R ..... ",7--i£ ~6 ,

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e =ledges used bY common murres

=black-legged IIltiiwake nesting area , I' '

1.......--. FOSSIL

POINT

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i' Figure 2. Nesting distriputions of black-legged kittiwakes and common murres, and plot locations on Chisik

,I and Duck Islands, lower Cook Inlet, Alaska. •

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. Figure 3. Seabird moLloring plollocalions on Gull Island and60-foot Rock, KachemakBay, Alaska.

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Gull Island, and to a lesser extent, 60-foot Rock, are frequently visited by tour and charter boats throughout the

breeding season. It is not uncommon for boats to approach within 25 m'of nesting birds (pers. obs.).

Flat llslands

Flat Islands, a small cluster of islands occupying 2.78 ha and owned by the English Bay Native Corporation, are,

located in Cook Inlet abour21 krn southwest of Seldovia (59°19'45"N. 151°59'45"W; Fig. I). The main island

is divided in nonh and south halves connected by an isthmus that is submerged at high tide (Fig. 4). The

shoreline consists of cobbles and bedrock, and the island is vegetated by a dense cover of herbaceous plants

with Elymus mollis and umbels dominating. Tufted puffins' burrows are found around the entire perimeter of

Flat I'lands except in areas where topography prohibits puffInS from taking flight or soils are too shallow to

accommodate burrows. '.

Recent population estimates for seabirds occupying these islands follows:

double-crested cormorant: ,2 birds

glaucous-winged gull: 2 birds

pigeon guillemot: 15-20 birds

homed puffIn: 4 birds

tufted puffm: 1000 birds

METHODS

More reSources were applied to the project in 1993 than in 1994. Two people collected data on a daily basis at

Chisi!: Island from 16 June to 14 September 1993, and additional observers helped complete population counts

in mid-June (one observer), and late July and early August (two observers). Crews of three or four people

count"d ledge-nesting seabirds on plots (Fig. 2) during four visits to Gull Island (9 and 23 July, 11 and 31

Augu':t) and three visits to 6O-foot Rock (20 July, 13 and 17 August). Two trips on 1 July and 17 August were

made to Flat Islands to monitor burrow-nesting tufted puffins.

In 1994, Chisik Island was visited, twice by two observers (5 to 13 July and 17 to 22 August), Gull Island and

60-foot Rock were surveyed by two to three observers on 30 June, I and 19 July, and 17 August. Flat Islands

were 110t visited in 1994.

Population Counts

Population estimates were made using two methods. The first consisted of counting all birds on an island

repeatedly and calculating a mean number of birds anending colonies, This method was used on Chisik and

Duck Islands and 60-foot Rock.

A second method, also employed on Chisik, Duck and Gull Islands, and 60-foot Rock, used a series of plots to

provide an index to population trends (Figs. 2 and 3). The number of seabirds using an island or a series of

plots was estimated by counting birds within permanent study plot boundaries established during, or prior to,

this study. Plot boundaries were delineated on photographs taken of cliffs located on each island. Plot size alld

location were chosen to,monitor a proponion of the total population (e.g" five percent on Cbisik Island) and to

subdivide the colony into easilyidentifiable units, Counts were typically made by two biologists in a watercraft

kept within 100 m of the plot. Using binoculars (8- or IO-power) and reciprocating counters to tally

individuals, the observers made repetitive counts until the difference between their totals Was ten percent or less.

Once obtained, the mean of the two counts was used as the population total for the respective plot. Population

estitrunes were made by combining the count total from all plots located on an island.

7

•

•

•

•

•

•

•

•

•

•

•
, ,_~T

~,

'I

BulTOWS

a = 1-14

'.

b = 15·20

c = 21-33

d = 34-39

e=40-44

f= 45-5B

g" 59-60

h= 61-72

1·9=coastal segments where

bulTOws were marked &

revisited

\

•

j

METalS

.-.. •• • •• • • • • • .-. .. • ilIo ._

..· .-.,. • • .-..- ... • • • •• · . • • • •

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• 7 • • • · =L .. • • • • • •. , . . 9 •• • ••.. . •. ...... .. .. -. • • • •• • •

• • • • • • • • •

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•• •

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......... 0 0 :,.. ..•• O·• .... . .)

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ii,

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Figure 4.

i

Tufted pufliD nesting distribution on Rat Islands, KachemakBay, Alaska. , . -

8
Population counts were made in late-June to mid-July when the maximum number of breeding birds was present

(i.e., before failed breeders left), and between 1000 and 1800 hrs when within-day variability in nest-site

attendance was lowest (Dragoo et al. 1991).

Using the procedures outlined above, counts of black-legged kittiwakes, pelagic cormorants. and common

mum,s were made on seven previously-established permanent plots on Chisik Island (Nishimoto etal. 1987)

and on an additional plot established in 1993 (Fig. 2). The additional plot was established in the only area

where adults remained throughout the breeding season. CoUnts of all ledge-nesting seabirds on Gull Island and

60-foot Rock were made on permanent plots previously established by AMNWR personnel.

Total island counts of nesting rufted pufrms occurred for the first time on Flat Islands as a pan of this srudy.

We recorded the number and stalUS of all rufted pufrm burrows located along the perimeter of Flat Islands in

early July. All active burrows (i.e., those with fresh excavation, shell fragments, feathers or droppings) were

uniquely flagged on the north half of the island and rechecked during a second visit in mid-Augus!. An estimate

of breeding success was determined by dividing the number of burrows still active during the second visit by the

totalilumber of burrows initially marked.

We used a different procedure to count pigeon guillemots. Observers anchored within 100 m of the guillemot

colony at Fossii Point on the northwest side of Tuxedni Channel, Chisik Island (Fig. 2) to count adults during

incubation and early chick rearing. Adults show territorial behavior during incubation (mid-June to mid-July at

other colonies), which optimizes counts of successfully breeding guillemot•. Tide state also influences adult

presence near colonies, so we attempted to conduct surveys near high tide (Andres 1993).

Phenology

Twelve land-based plots were used to follow breeding events and productivity of black-legged kittiwakes and

common murres on Chisik Island. These plots were visited every 2-3 days to record reproductive starus (e.g.,

clutch. size, hatch, and fledging) of each nest until the birds depaned. Since the eggs and chicks of common

murres are difficult to see, observers relied on behavioral cues to indicat~ reproductive starus (after Mendenhall

et al. 1991). Birds exhibiting incubating postures during three consecuti~e visits were considered to have an

egg, 'lOd birds showing brooding posrure (see Byrd 1989 for description of behaviors) were assumed to have a

chick. We used direct observations of eggs or young for kittiwakes. Phenology of horned puffins was

determined by examining occupied crevices to record the presence of eggs or chicks about once every five days.

In cases where the reproductive stalUs of a site changed between visits, we used the intermediate date between

the two visits.

Productivity

Procedures for estimating productivity varied among species depending on access of sites for observation.

Cormorant productivity was determined by counting the number of chicks produced per nest on each plot where

cormorants auempted to breed. Active nests were defined as those having vegetation added during the current

breeding season. Crude estimates of glaucous-winged gull productivity were made by counting maximum

numbers of chicks on plots.

For bl.ack-legged kittiwakes productivity was determined on Duck and Chisik Islands in 1993 by monitoring

active nests within designated plots throughout the breeding season. We defined active kittiwake nests as we did

for cormorant nests, i.e., those containing vegetative material added in the current breeding season. Twelve

land-based plots (Fig. 2) were established, eight on Chisik and four on Duck, where nest contents could be

viewo1 with binoculars and spotting scopes, or a six m pole with a mirror. attached to the top. From each plot,

we counted: I) the total number of nests, 2) the number of nests with one or more eggs, 3) the total number of

eggs, 4) the number of nests with one or more chicks, 5) the total number of chicks, 6) the number of nests

where one or more chicks fledged, and 7) the total number of chicks that fledged (after Dragoo and Sundseth

9

•

•

•

•

•

•

•

•

•

•

•
It

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!

It

•

•

Ii

",

•

•,

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•

•

...~:"'_ ...o·· I ,",.

1993). Using plots as the sampling unit for analyses, we used a nitioestirnator (Byrd 1989) to estimate the

following parameters: I) clutch size, 2) nesting success, 3) hatching success, 4) chick success, 5) egg success.

6) fledging success, 7) rep:roductive success, and 8) overall productivity. The fmal two parameters are defined

as the number of nests where 2-.0ne chick fledged/number of nests with 2.0ne egg. and the number of nests

where 2. one chick fledge'd/total nest starts, respectively. The reproductive parameters listed above are

commonly used in other s~dies of seabirds and allow inter-year comparisons within a colony and within-year

comparisons among colonies to be made easily. ,

At Gull Island and 60~foa! Rock we also used plots to monitor kittiwake productivity (Fig. 3), but visits were , less frequent and observations were made from the water.

For common murre produbtiVity, observers recorded: I) the number of sites with one or more egg, 2) the

number of sites with a chick, and 3) the number of sites where a chick fledged (after Dragoo and Sundseth

1993). Data were used td estimate hatching success, fledging success, and reproductive succes~ (as defined

above). Chicks were assJmed to have fledged if ihey were II days or older when sighted last.

Productivity of homed pJffins was estimated on Duck Island in 1993 by monitoring a sample of nesting crevices

that could be examined cdnsistently (i.e., crevices into which a light beam could reach the end). Crevices were

checked once per week ftom late June through mid-September for the presence of eggs, chicks. and adults.

Since each crevice contaibed an egg when the study was initiated, estimates of productivity were limited to

hatching and fledging suctess. Homed puffins do not nest on any of the other islands included in this study.

Chick Growth & Diet

Growth rates and diet of homed puffin chicks were monitored at crevices on Duck Island from mid-July to

mid-September 1993. Ctlicks were removed from uniquely flagged crevices twice per week, weighed and

measured for right wing thord length before being returned to the proper crevice.

To obtain estimates of siL and species composition of food eaten by chicks, we collected prey brought to , crevices by adults. Crevice entrances were blocked by squares of hardware cloth (about 25 x I em mesh) after

adults had departed to fetd and were typically rechecked after 3-5 hours. Adults sometimes drop their prey at

the crevice entrance wheh access to their chick is blocked. Prey were measured, weighed, and returned to the

chicks in most cases. pr\,y that could not be identified were collected, labelled. and preserved in formaldehyde.

We also collected prey sbples opporrunistically when found at an unflagged crevice entrance. On one

occasion, prey samples J,ere taken from five crevices where chick growth was also being monitored. Although

this may have minimally affected chick growth, we 'assumed that the absence of one meal would not affect the

overall growth rate.

RESULTS & DISCUSSION

Chisik and Duck 'Islands

Double-crested cormoJnt

pOPulationS.--IJI993. double-erested cormorants were observed occasionally on the cliffs of both

islands. Although they rere not present on eStablished population plots on Chisik Island in 1993 or 1994 (Table

I), a nesting colony of about 60 adults was found 300 m north of the Snug Harbor cannery and a colony of

about 100 individuals wb on the northeast cliffs of the island. The latter figure is only approximate because the

colony is located appro~imately 600 m above sea level and is difficult to observe.

10
•

Table I. Summary of double-crested. pelagic. and red-faced cormorant population estimates on plots in lower

Cook Inlet colonies.

Location Year Estimate iI Source Comments •

DCCO' PECO' RFCO' Unknown

species

Chi!:ik 1986 I (I) 0 0 4 (2) Nishimoto et aI. 1987

Island 1987 I (I) 0 Beringer & Nishimoto

(p1ms 1-7) 1988

•

1993 0 0 0 0 this study

1994 0 0 0 0

Gull Island 1986 0 55(20) 0 Nishimoto & •

Thomas 1991 plots 1-8

1987 O· 44(15) 0 plots 1-8

1988 0 43(21) 0 plots 1-8

49(22) plots 1-10

1989 0 30(16) 0 plots 1-8

33(16) plots 1-10 •

1990 0 38(21) 0 plots 1-8

39(21) 1(1) plots 1:10

1992 0 6(5) 0 Erikson, unpubl. plots 1-8

6(5) 1(1) data plots 1-10

1993 0 39(25) 0 this study plots 1-8

41(26) 0 plots 1-10 •

1994 0 43(26) 0 plots 1-8

44(27) 0 plots 1-10

60-foot Rock 1985 0 0 0 Nishimoto et aI. 1987

(plots 1-2) 1986 0 0 0

1987 0 0 0 Nishimoto '& Beringer 1989 •

1988 0 0 0

1989 0 (2) 0 Nishimoto & Thomas 1991 .

1990 0 0 0

1993 0 3(0) 0 this study

1994 0 0 0

• eSllmate IS the mean of counts pooled for plots. nests In parentheses • , double-crested cormorant

, pel:tgic cormOrant

, red-faced cormorant

•

•

11

•
II

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I

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I

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•

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::

Ii

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•

•

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i',

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ii

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•

•

ii

;

i!

Roosting double-crested conri;rants were seeA~b~ and near murre ph,duciivity plots 5 and 6 on Duck Island on

an irregular basis. The nu'mber of roosting birds peaked in the late afternoon. with a maximum of 155 birds

observed on 21 August. Sbme of them may have been young-of-the-year that hatched on Chisik Island.

Although double-crested J~orants were more abundant than pelagic ~ormor;'nts at Chisik Island. less is

known of their breeding adtivities because they tend to breed on higher. less accessible and less visible cliffs,

Counts of double-crested tormorants on Chisik and Duck in 1993 (160 birds) were similar to counts in 1983

(150), but lower than estirktes in the early 1970s (Appendix I). "

Pelagic Connorant

Populations.--Pelagic cormorants did not use any established plots. and fewer than 30 adults constructed

nests in the vicinity of ou~ plots in 1993. This nesting area appeared to have undergone significant physical

changes resulting from rock slides prior to our visit in July 1994. Consequently. there was no evidence that

cormorants used this area in 1994. In fact. only two pelagic cormorants were seen during the two brief visits to

Chisik in 1994,

,

Colony numbers were similar to counts in the early 1970's (AppendiX I). It appears that Chisik Island has been

used fairly consistently by' pelagic cormorants over time with a maximum of about 30 nesting birds, Strong I

conclusions regarding the breeding population are difficult to make, however, because cormorants show variable

site fidelity. '

'Breediile PhenoI02V.--Twelve nests were built between 16 June and 12 July 1993 on cliffs between

plots 3 and 4. We had no vantage point to view nest contents, so status could not be determined until chicks

grew large enough to be ~een from the water. There are no data to compare time of nest building or other

phenological events.' I',' , " '

Productivity.-"Despite daily monitoring of nests near productivity plots. no young were observed in

1993 and all'I2 nests wete abandoned by 13 -September, suggesting complete failure. No pelagic cormorant

nests were found in 1994!

Cormorant breeding activiit;es have not been studied rigorously on Chisik Island, so productivity data are

limited. but it does not appear that pelagic cormorants have successfully produced young in any years of study , (Nishimoto et al. 1987, Be;mger and Nishimoto 1988, this study).

GllIucous-winged Gull

Populations.--In 1993. an average of nine adult glaucous-winged gulls was counted on plot 3 (SD=7.3,

n=9). and adults roosted in very low numbers but did not nest on plot 4 (i.e., <5). 1Ii. 1994, plot 3 had a

mean of ten adults (SD~2.4, n=7; Table 2)., Our counts indicate that consistent numbers of gulls used the

plots in both years of this study but higher numbers were recorded in 1986 and 1987 (Table 2).

We could not accuratdy count gulls on Duck Island because of dense vegetation but fewer than 100 gulls

appeared to be present. About 224 breeding glaucous-winged gulls were also present in a colony about 300 m '

north of the Snug Harbor cannery on Chisik Island: Here, too, dense vegetation precluded an accurate count.

An unknown number of 19u1ls nested near the top of the high cliffs on the southwest tip of Chisik.

I '

, ' : ,,'

The glaucous-winged gull 'population at Chisik and Duck Islands appears to have declined since 1978 when

numbers were estimatedlat 1500-2000 (Jones et al. 1980, Muhlberg 1984). Muhlberg (1984) estimated that

about 300 adults used the area north of the cannery in 1983; 75% more than we counted in 1993. We estimated

that fewer than 1000 gla6cous-winged gulls probably used Chisik and Duck Islands in 1993 and 1994 (Appendix

2).

12

•
Table 2. Summary of glaucous-winged gull population estimates on plots in lower Cook Inlet colonies.

Chisik

Island b

(plot, 1-7)

Gull Island

(pIOl; 1-10)

sgl cnt on 8/15

60-fc,ot Rock

(plot:; 1-2)

• estimate is the mean of counts pooled for plots, nests in parentheses

b includes Duck Island

13

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•

•

.,

•

•

•

•

•
11

•

Ii

I'

I~ 1978. the nesting distribution of glaucous-v:..ingedgulls included thtn,oasts ofabout the southern two-thirds of , ,

Chisik Island and all of Gull Island (see Jones et aI.1980). We found similar distributions but could nOl

reliably estimate the numbdr of birds breeding along the high cliffs and beneath vegetation. '

" Breeding PhenoloL.--In1993, rwo active nests were observed on plot 3 on Chisik Island on 28 June.

Three nests were counted dne month later at the colony north of the cannery, and chicks were seen there in ,

mid- to "ite August during reaChed bird surveys. Phenology was not assessed in 1994. .

,Productivity .--Nest contents on plot 3 could not be determined from our observation location On the

water and it is possible that vegetation obscured chicks near the nests. No fledglings were seen in 1993, and

only one chick was observJd on twO occasions in 1994.

Glaucous·winged gulls usJ both plots 3and 4 in 1986'and 1987, but only plot 3 in 1993 and 1994. Mean

numbers of adults have dedlined 'on plOt 3 since 1986 when it was calculated at 18; the average number of adults

counted in 199:1 was nine .inC! ten in 1994.

The low numbers of nests b~ plots (i.e., three on plot 3 in 1993) and our inability to see and follow chicks '

yielded little information 06 productivity. In 1983 Muhlberg (1984) first observed chicks in late June. Our

arrival at Chisik Island in kd-June in'I993 could have coincided with the end Of incubation so that the number "

of active nests on plots may have been low.

I '

Our periodic countS of g~lls at the colony north of the cannery in 1993 iIidicated at least 20 young were present. , This number is undoubtedly low because chicks are easily overlooked. They are cryptic, hide in vegetation and

are difficult to observe frob the beach.

Black-legged Kittiwake

Populations.--Index plots were set up at Chisik in 1986.to proyide a basis for monitoring population

trends without having to Jnsus all the birds on the island. Counts of kittiwakes on these index plots in 1993

and 1994 were lower thanlthe totlils for 1986 (Table 3). Nevertheless, it appears there may have been unusually

high attendance of kittiwakes at the colony in 1986 based on other counts in the early 1980s (Appendix 3).

I ' The earliest counts of kittiwakes reported for Chisik were in 1936 when Murie (1959) estimated 25,000 birds

were present. Most counls and estimates in the 1970s ranged from 20,000 to 28,000 kittiwakes (Appendix 3).

An exception was in 19711 when Snarski (1974) counted over 47,000 kittiwakes at Chisik, but he apparently

included chicks making that count incomparable. Since 1983, counts have generally been 20,000 or less except

for 1986 which was partidularly high, as indicated above. Counts in 1993 and 1994 were slightly lower than

previous counts, and therd appears to have been a slightly declining trend at Chisik in numbers of kittiwakes

since 1970 (Fig. 5). I: .. ' . . Breedmg Phenology.--Kitltwake nests were already constructed and some eggs were "ud by the ume

observers arrived at stUd~ plots on 16 June 1993. In 1993 egg-laying and hatching occurred on dates similar to

those previously recordedl for the islands (Table 4). All eggs hatched between 9-15 July 1993. In 1994 young ,

chicks were present on plbts by 6 July when we first visited Chisik; all chicks fledged on or before 18 August.

In almost ~very year whelebreeding phenology data were collected, the breeding effort largely failed (Table 5).'

Reproductive failure hastisUaIly occurred during the incubation period. This may be due to reduced parental

care reSulting from food ~tress Which, in tum, is induced by insufficient prey near the colonies (Snarski 1974,

Jones et aI. 1980, Kafka 11984, and Multlberg 1984). Consequently, adult kittiwakes must forage far from

breeding sites. In contrast to 1993 when few kittiwakes were seen feeding near land, cannery caretakers

reported seeing kittiwake~ feeding upon schools of sand lance in the southern entrance of Tuxedni Channel in

mid-June 1994. '

14,
Table 3. SUminary of black-legged kittiwake population plot counts at lower Cook Inlet colonies.

Location Year Estimate , Source Comments

Chi,;ik' 1986 1498(1201) Nishimoto et aI. 1987 completed in July

(plots 1-7) 1987 (626) Beringer & Nishimoto completed in July

1988

1993 919(569) this study . completed in July

1994 1045(996) this study completed in July

Gull Island 1984 145(80) Nishimoto et aI. 1987 plots 1-3

1985 149(56) Nishimoio et aI. 1987 plots 1-3

1986 224(158) Nishimoio et aI. 1987 plots 1-3

993(769) plots 1-8

1987 213(101) Beringer & Nishimoto plots 1-3

725(300) 1988 plots 1-8

1988 240(189) Nishimoto & Beringer plots 1-3

1289(949) 1989 plots 1-8

1454(1071) plots 1-10

1989 234(164) Nishimoto & Thomas plots 1-3

1082(875) . 1991 plots 1-8

1219 plots 1-10

1990· 218(164) Nishimoto & Thomas . plots 1-3

1156(817) 1991 plots 1-8

1301(929) plots 1-10

1992 191(135) Erikson, unpub. data plOIS 1-3

1027(600) plots 1-8

1165(685) plots 1-10

1993 222(94) this study plots 1-3

909(515) plots 1-8

1025(571) plots 1-10

1994 204(138) this study plots 1-3

926(751) plots 1-8

1067(847) plots 1-10

60-foot Rock 1985 (35) Nishimoto & Beringer 1989

(plots 1-2) 1986 96(75) Nishimoto & Beringer 1989

1987 71(31) Nishimoto & Beringer 1989

1988 112(82) Nishimoto & Beringer 1989

1989 98(90) Nishimoto & Thomas 1991

1990 101(88) Nishimoto & Thomas 1991

1993 65(47) this study

1994 103(89) this study

• estimate is the mean of counts pooled for plots, nests in parentheses

, includes Duck Island

15

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• "

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, . ->'6:1

• ~,,(

'4~'";,;'t¥-.." -~~ ,co. ...,+t~·..-:-.,.I"'tl'! .&6:1~,,( • C':!6'6'

,,(

<96'

,,(

<'c9.

• (51,,(

1.9c9.

en •

(51,,(

-9c9. U (51,,(

C .&c9.

ce (51,,(

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en ~c9.

- (51,,( ~.

CO

~c9. 0)'

e..:> (51,,( ~.

:::::l ,,( .

<96' 0 0, ,,( -...;,. <96' .- • 6'',,( en t

~6' , .-

.s::. • ,,(

(J <9<,:6',,(

6'",

·.

6'",

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• • 6'",

6'", ,

'0 In 0 to 0 06'&

C":l C\l C\l ..... ...... ~'" I (SOOO~) Sa>ieM!ll!)l~O SJaqwnN

Figure 5. Populationtr'ends of black-legged kitiiwakes based on wbole-island counts at Chisik Island, lower , Cook Inlet, 1970-1994.

.. 16

j
17

••
,I

•

Table 5, Summary of black"leg'ged kittiwake.productivirv on plots at lower Cook Inlet colonies. , , I ; .

Location Year I # Nests' Productivity' Commems Reterences

•

;1

I:

'I

I,

:1

•

1;

.(

•

•

.:;

i'l

ij

I'

•

Chisik

Island'

Gull

Island

60-foot

Rock

(plots 1-2)

1970 ___d 0.0

1971 74 0.0

1973 "very good"

1978 115 0.02

1979 60 0.36

1983 90 0.0

1986 1201 0.25,

1987 626 0.0

1993 341 0.0

1994

1984 80 0.80

1985 428 0.33

1986 769 0.69

1987 300 0.03

1988 1071 0.63

1989 985 0.53

1990 929 0.47

. 1992' 685 0.36

1993 608, 0.10

1994 847 0.21

1985 35 0.16

.1986 75 0.61'

1987 31 0.00

1988 82 0.63

1989 90 0.01

'- 1.5 young/nest

in sample area

no chicks on cliffs,

but 11 fledglings seen

later with adults

plots 1-7'

plots 1-7; fledging mostly

done by 2nd visit; 31

fledglings: 1,624 adults seen

near the SW cliffs

plots 1-3

plots 1-8

plots 1-8

plots 1-8

plots 1-10

Snarski 1970

Snarski 1971b

Snarski 1974

Jones & Peterson

1979

Jones et al. 1980

Muhlberg 1984

Nishimoto et al. 1987

Nishimoto ('&*)&%(

this study

Nishimoto et al. 1987

Nishimoto &

Beringer 1989

Nishimoto &

Thomas 1991

Erikson,

unpublished data

this study

Nishimoto et al. 1987

Nishimoto &

Beringer 1989

Nishimoto &

Thomas 1991

i,

'!1

;i

•

'I,

•,;

•

I'

1990 88 0.02

1993 47 0.02 this study

1994 89 0.04 this study

a dete~mmed from the mean of counts pooled tor plots

'b calculated from the me:u\ number of chicks/nest (using the max number of chicks during replicate

counts)'unless Otherwisetnoted

, includes Duck Island :

d single count of nests on I 5 August

- counts not made for p~oductivity

18
Productivitv.--In 1993, we monitored the fate of 341 nests. Eggs were laid in 60% of the nests: average

clutch size was 1.47 (35 % had one egg, 32% had two eggs, and 3% had three eggs). Of the 305 eggs laid in our

srudy area, only two hatched. Neither chick survived to fledging, and f"e saw only about five .fledglings on the

entir,~ island. Clearly, in 1993 there was nearly total reproductive failure, based primarily on egg loss to predation

by bald eagles and common ravens. Ptedation may have been exacerbated by irregular incubation by adults which

was observed in early July. Presumably temporary nest abandonment was due to food stress. Most of the

kittiwakes had left the colony by 6 August.

In 1994, we got only indirect evidence of reproductive success, but it appeared productivity was higher in 1994

than in 1993. On 7 July we checked 333 nests; 23% were still active compared to only 5% still active at this

date in 1993. 'Of the 77 active nests, 23% had one egg, 13% had two eggs, 27% had one chick, 22% had two

chicks, and the remaining 14% had one egg and one chick. During our.second visit to Chisik in mid-August

1994, most kittiwake chicks had fledged, and we counted 31 fledglings in a group of about 1,600 adults near the

southwest cliffs. In addition, we regularly saw fledglings elsewhere (Table 5).

Alth"ugh the quality of information about productivity of kittiwakes varied, data are available for ten different

breeding seasons at Chisik (Table 5). Kittiwakes had nearly complete breeding failures in at least six years, and

productivity was 0.25 or more in three years. As indicated above 1994 was not a year of failure, but the rate of

succ,'ss cannot be estimated.

Common Murre

Populations.--The number of murres counted on index plots at Chisik was similar in 1986, 1987, and

1994: but fewer birds were present on these plots in 1993 (Table 6). The reduction in 1993 likely did not

represent a population decline, but instead, it probably reflects reduced levels of colony attendance due to low

food availability and poor reproductive success (see below). In spite of the lack of evidence of a trend since

1986, it appears there was a substantial reduction in numbers of murres at Chisik between 1970 and 1978, and

another decline between 1978 and 1983 (Appendix 4, Fig. 6).

Further supponing the suggested decline was evidence of a reduction in nesting distribution of murres at Chisik.

Approximately 150-200 murres were counted in 1971 (Snarski 1971c) among the kittiwakes on the southwest

cliffs, Fewer than 100 murres briefly visited this area in 1993. but did not rerum to breed. Furthermore, no

murr"s were seen in this area in 1994. '

Breeding Phenology.--Because land-based plots on Duck Island were established late in 1993,

phenological evenis were ascenained from anecdotal information. Common murres 'were congregated near and .

on cliffs when observers arrived in mid-June. Most murres never attended cliffs regularly on'Chisik Island, but

birds continued to visit Duck Island cliffs inconsistently through early September. Although eggs were first

observed on.8 July away from srudy plots on Duck Island, egg-laying did not take place until mid-July within

srudy plots. Common murre chicks began to hatch on 23 August within :our srudy plots, with the average hatch

on 29' August (SD=4.2. n=6). The mean fledging date was 11 September and ranged from 7 to 13 September

(SO=2.I, n= i7).

In 1994 we found one common murre egg on productivity plot 4 on 6 July. It was gone the following day and

no odler eggs were seen until 12 July. Thus, it appeared that breeding phenology began similarly to that·

observed in 1993.

Productivirv.--Common murre productivity was estimated by monitoring six plots on Duck Island (Fig.

3) from 15 August to 14 September 1993. In 1993, 80% hatched of 41 eggs present in our plots in midAugust, and 55% (18) of the chicks fledged (Appendix 6). Overall productivity was about 44%, slightly lower

than the normal range for this parameter in Alaska (Byrd et al. 1993). This estimate is probably too high

because most eggs were within ten days of hatching when they were first observed, so egg loss prior to that

19 !

I

•

•

•

•

•

•

•

•

•

•
•

_Lo~ca_t_lO_n ~Y_e_ar_1 Esumate • Source Comments

•

Table 6. '. ,~~~:,'__ ,_,_:~_.p l. .. '-.~:Summary of common mutTe population ·plot counts for lower Cook Inlet colonies.

I

.. I • estimate is the mean ·of counts· pooled for plots

b includes Duck Island .

plots 1-3

plots 1-3

plots 1-8

plots 1-3

plots 1-8

plots 1-3

plots 1-8

plots 1-10

plots 1-3

plots 1-8

plots 1-10

plots 1-3

plots 1-8

plots 1-10

plots 1-3

plots 1-8

plotS 1-10

plots 1-3

plots 1-8

plots 1-10

plots 1-3

plots 1-8

plots 1-10

courits done between

19 June & 7 July

non-breeding

aggregation

non-breeding

aggregation

this study

this study

Nishimoto & Beringer 1989

Erikson, unpublished data

Nishimoto & Thomas 1991

Nishimoto et al. 1987

Beringer & NishimolO 1988

this study

.Nishimoto & Thomas 1991·

• 337

392

173

342

49

67

107

103

158

84

227

228

112

184

i 202 , 136 <

236 •

250

196

327

334

60

315

328

201

324

333

23

·33:

34

20

25

18

23

II

1994

1990

1992

1993

1987

1985

1986

1989

1986

1987

1993

1994

1988

1993

1994

60-foot Rock 1985

(plots 1-2)' 1986

1987

1988

1989

1990

Gull Island

Chisik Island b

(plots 1·7)

,

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20
, en

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u

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.:::s:::

.-

en .-

..c

()

LO

C\I

o

C\I

LO

..... o

..... LO

•

•

•

•

•

•

•

•

•

{spUEsnOl·uJ SSJJnlAJ JO JsqwnN

Figure 6. Common murre population trends based on whole·island'counts at Chisik and Duck Islands. Alaska.I

21

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date would not have been observed. Additii:irlill evidence of reduced s\lctess in 1993 was that most murres on

Chisik never settled into t~e normal nesting routine. Birds:remained flighty throughout the summer. and even within

the 'middle of the nesting penod, major sections of the nesting area there were devoid of birds.

We did not measure productivity of murres in 1994. but during our counts, birds seems to be acting more normalIv

(i.e ... most birds remaineti on cliffs when we approached) than in 1993. There are no prior data on mu~e I

productivity at Chisikor !Duck for comparison.

Pigeon Guillemot

Populations.--The only site believed to be used for breeding by pigeon guillemots in both years was at

Fossil Poin't. On the west lide of nonhem Tuxedni Channel. We completed five counts in early July and

obtained a median of 13 atiults (range 1-19)'in 1993; 13 were observed during the only count made in 1994.

Nesting colonies of PigeoJ guillemots are relatively sm~1 in comparison with other seabirds, but range from

about 4-48 individuals (Sahger and Cody 1994). Colony size may be limited by nesting habitat availability,

access by predators, and ~roximity to adequate food sources. Because counts were made in early July, some of

the adults present may have been failed or non-breeders. Our counts may reflect 50-75 percent of all breeders

attending the Fossil Point bolooy (Katherine Kuletz, Migratory, Bird Manage., pers. comm.). .

I , . Previous information 00 pigeon guillemots in the Chisik Island area is anecdotal. Krohn (1966) suspected that

guillemots nested along thb, east shore of Chisik and' stated adults were "very abundant." Gabrielson and

Lincoln (1959) found guillemots nesting among black-legged kittiwakes and common murres 00 Chisik in 1940

(no details on the exact lobations were given). We found no evidence of breeding !'O the east shore of Chisik.

In fact, guillemots were sJeb infrequently throughout the summer near the southern tip and nonhwest shore of , , Chisik Island. Low rock faces at the latter site, similar in composition to Fossil Point, may provide nesting

sites but wer~ not investig~ted thoroughly in 1993 or 1994.

Homed Puffin

Populations.--A total of 30 crevices was monitored on Duck Island in 1993. Crevice surveys represent.

only a ponion of the totallbreeding population based on the presence of about 700 adults loafing on the water

adjacent to Duck Island during the incubation period. Concentrations of homed puffins were also noted along

the southwest coast of Chibk Island, where about 40-50 adults were frequently seen in 1993. '

, We did not a~temPt to estiLte the current breeding population, but our casual sightings (see above) may

indicate a decline in the n~mber of homed puffins usiog Duck Island. Jones et al. (1980) estimated that 6000

homed puffins bred at Duh' Island in ;978 and 1979; Mublberg (1984) estimated 5000 in 1983.

Breeding PhenoloL.--Adults with eggs were found in 67% of the crevices we examined during initial

surveys on 23 and 25 Jun~. , The remaining 33 % of the crevices contained only adults. The mean of hatch

occurred 27 July (SD=6.1, n = 14), and the mean date of fledging was 2 September (SD=5.7, n = 12; from

Table 7). Timing of thes.! events fell within the ranges recorded during previous srudies except that hatching , began one day earlier in 1993 than in other years, (Table 7). It,

Productivity.--About 53% of the 30 eggs we monitored hatched and 69% of the eggs that hatched

fledged young (Table 8)'lwe estimated that, overall, 37% of the pairs fledged young. ,

Hatching success was withio the range recorded in other years, but chick monality may have been higher than

usual at Duck Island (Table 8). Overall, the number of young fledged per pair fell withm the ranges calculated

in 1978 and 1979, but the average for homed puffins in Alaska is higher at 57% (Byrd et al. 1993).'

22

1

•
•

Table 7. Breeding phenology of homed puffins at Duck Island, lower Cook Inlet, Alaska, 1978-1993.

Year Egg-laying Hatching Fledging Source • 197~: 5-29 June 18-27 July 28 Aug-19 Sept Jones et al. 1980

1975' 15 June-4 July 25 July-4 August 30 Aug-II Sept Jones et al. 1980

1983 < 10 June-? 16 July-II August Muhlberg 1984 •

1993 < 23 June-? 15 July-7 August 3-> 13 Sept this study

•

•

•

•

•

•

•

23

•
Table 8. . . l;0.". "'-

Summary of horned puffin productivity at Duck Island, lower Cook Inlet, Alaska.

•. I . .' .

Year

1978

1979

1993

Hatch I

success

0.73

0.44

0.53

Broods with -'

fledged young

0.92

0.71

0.69

Mean .# of young

raised/pair

0.60

0.24

0.37

Source

Jones et al. 1980

Jones et al. 1980

. this study

•

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.,. t. 11.' 1
Chick Growth and Diet.--Sixteen chicks were weighed and measured an average of 12 times from late

July;;o mid-September. A regression equation representing body condition follows: weight=2.719 (wing chord)

+ 16.249 (r'=0.90, n = 109). Figure 7 shows average chick mass change per day (9.4 g).

Chick growth in horned puffins in 1993 was similar to results obtained in 1978 and 1979. Two chicks in 1993

attained greatermasses prior to fledging than weights recorded in other years at Duck Island.

Diet ,;amples (n = 30) consisted primarily of Pacific sand lance but includ,d an additional six fish whose

identification is pending. The average total length of fish was 87.9 mm (SD=24.0, n= 105, Appendix 6).

No data are available for direct comparisons of the sizes of fish fed to horned puffm chicks at Duck Island.

However, in all years PacifIc sand lance comprised the majority of feedings (Jones et al. 1980, this study).

Jones et al. (1980) observed only two instances in which identified fish were not sand lance; three capelin

(Mallorus villosus) and two pink salmon (Onchorhynchus gorbuscha) comprised those samples.

Little is known of horned puffm diets in other pans of Alaska, panicularly for chicks (John Piatt, Natl. BioI.

Serv., pers. comm.). However, we compared results of chick diets from a single study completed at Hall

Island, Shumagin Islands, Alaska, in 1976 (Moe and Day 1977; Table 9): .Duck Island puffins were nearly

exclusive in bringing sand lance to chicks hetween I and 10 August, while Hall Island horned puffins relied on

three primary species (sand lance, capelin, and Pacific cod (Gadus macrocephalus) between II and 28 August.

Sand lance fed to chicks at Duck Island were smaller than those delivered to Hall Island chicks (Table 9).

AJthough prey availability at each of the sites is unknown, sand lance appear to be an imponant component of

horned puffin chick diets.

Gull Island

Pelagic Cormorant

Populations.--Averages of 41 and 44 adult pelagic cormorants were observed on the Gull Island index

plots i>1 1993 and 1994, respectively (Table I). Numbers of adults and neSts have remained relatively stable on

plots since they were established in 1986, except for an unusually low count in 1992 (Fig. 8, Table I). Counts

of pel'gic cormorants for the entire island made in 5 years between 1976 and 1990 were also relatively stable

(Appendix I).

Because cormorants sometimes use different sites for breeding from year to year, it is difficult 10 assess

population changes. For example, Nishimoto and Thomas (1991) found that numbers of adults on plots showed

a mod"rate increase, while total colony counts indicated a slight overall decrease.

\ .

BreedingPhenology.--In 1993, we saw no chicks at Gull Island on 9 July, bur chicks were presem

during our next visit 23 July, and cormorants had left the island by 31 August.

In 1994, we saw no chicks during a check of the island on 19 July, bur chicks had hatched by the time of our

next vi"it on 17 A~gust. Chicks were still presem when we visited the island for the final check on 23 August

1994.

Productivity.--A total of26 nests and 19 chicks was checked three times in 1993; on 23 July, and II

and 31 August. AJI pelagic.cormorants were .gone fr<lm GuJl Island plots by 31 August. Assuming chicks last

seen II August fledged, productivity averaged 0.73 young per active nest in 1993.

In 1994,27 nests observed on 19 July had 30 chicks on 17 August. Twenty-two chicks (0.81 young per active

nest) w"re still present in nests during the last survey on 23 August.

25

•

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500

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• • · • • • , • • • • • • • 300 8 ,

8 • • • • • 8

• 8 • • • • • • • • • • 200' • ·" • • • • • • • • • • 8 • • • •

I • 8 • • 100 • • • • • • • 8 • • • 8 • • • • • •

• •

0

200 210 220 230 240 250 260

Julian date

•

.,

Figure 7. Mass changes of horned puffin chicks at Duck Island, lower 'Cook Inlet, Alaska, in 1993.

26

1
. . Table 9. Comparison of tbe relative imponance of different fish specie's in bill loads of homed puffins at Hall

Isla;1d, Shumagin Islands. 1976', and Duck Island, 1993.· .

•

Species Number Caught (%)

Hall b Duck'

.Ammodytes hexapterus 107(66.5) 108(93:9)

MaUorus villosus 34(21.1) 0

Gmius macrocephalus 17(10.6) 0

Trichodon trithodon ·1(0.6) 0

Onchorhynchus gorbuscha 0 0

Unidentified flatfish 1(0.6) 0

Unidentified larval fish 1(0.6) 0

Unidentified juvenile fish 0 7(6.1)

• 1976 data from Moe and Day 1977

bN=161·

, N = 115

d N=45

, N=32

r N=30

Total Weight in gm (%) %Freg. of Occur.

•

Hall b Duck d Hall' Duck r

211.4(70.3) 148.2(94.3) 68.8 96.7

I

62.1(20.7) 34.4 •

I

24.9(8.3) , 6.3

0.9(0.3) i 3.1

•

0.6(0.2) 3.1

0.5(0.2) 3.1

9(5.7) 20.0 •

•

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28

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•

Population trends of pelagic cormorants on plots at Gull Island, lower Cook Inlet, 1986-1994.

,

,"

Figure 8.
--

Our index to productivity on Gull Island plots was similar in both years of this study and fell within the range

calculated from past years (Table 10). Overall, productivity in 1993 anq 1994 was lowe, than the mean

calculated from previous years (n=6), a significant decline (p=0.09). '

Glaucous-winged Gull

Populations.--We found only two adult glaucous-winged gulls on p'lots at' Gull Island in

1994, down from 20-30 in previous years (Table 2). Nevertheless, relatively few of the gulls using Gull Island

are on our cliff plots. Most occur on top of the island, and whole island counts between 1976 and 1990 suggest

the population increased Over that period (Appendix 2).

Productivitv.--A maximum of six chicks was observed on Gull Island plots in 1993 and tWo

chicla: were seeil in 1994. These numbers do not accurately assess glau,,?us-winged gull productivity; they only

sugge:it that some production occurred. ' '

Black·legged Kittiwake

Populations...·Approximately 900 adult black-legged kittiwakes were counted on plots 1-8 at Gull Island

in 1993 and 1994 (Table 3). Numbers have been relatively stable on plots since 1986 when they were first

established (Fig., 9). Nevertheless, whole-island countS made in 1976, 1985, and 1990 suggest kittiwakes

increm;ed at Gull Island between the mid-1970s and the mid-1980s (Appendix 3).

Breeding Phenology.--In 1993 Gull Island was visited too infrequently to calculate prec'ise dates of

breeding phenology. However, no chicks were present on 9 July, but hatthing had begun by 23 July. Most

succes"ful nests had chicks on II August (63 chicks in five plots), and many fledglings were seen on ledges and

in the ;mrrounding water on 31 August (34 on ledges and at least 100 in the water).

In 1994,43 nestlings were recorded on 19 July, our first visit since the beginning of the month. Most chicks

had fledged by 23 August (Table 4). '

Productiviry.--A mean of 608 and 847 nests was constructed by biack-Iegged kittiwakes on plots on

Gull Island in 1993 and 1994; respectively. Although eggs and young chicks were not visible during

observ"tions from the water, older chicks could be counted. All nests with chicks on Gull Island contained

broods with one chick in 1993, while in 1994 six nests contained two chicks each.

Although numbers of adults on plots in 1993 and 1994 were comparable, more nests were seen in 1994.

Overall productivity was calculated at 0.10 chicks/nest for Gullisfand in 1993 and 0.21 in '1994 (Table 5).

Inter-annual comparisons of reproductive data on Gull Island plots indicated a highly significant difference in r'

numbers recorded between 1988 and 1993 (p<O.OOI; Table 5), and similar differences were shown in

comparisons of 1988 and 1994 data (p=O.OOI).

Common Murre

Populatioils.--Approximately 320 murres were counted on plots 1-8 at Gull Island in 1993 and 1994

(Table (,). Although numbers have been stable since 1992, there has been a significant (p<O.OI) increasing

trend in murres on plots since 1986.(Fig. .10). Furthermore, whole-island counts increased from approximately

2000 to 3000birds from the mid-1970s to the mid-1980s to over 5000 birds'from 1988-1990 (Appendix 4). An

inexplicably low count was reponed for 1991 (Erikson 1993), the last time a whole-island survey was done. , ,

Breeding Phenology.--Gull Island was visited too infrequently to accurately assess phenological events, but we

noticed an egg as early as 30 June 1994.

29

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Table 10, Summary of pelagic connorant productivity on Gull Island plots, 1988-1994.

I .' ~7""c," Year No. of dhicks/nests , Source

~:

•

1988

1989

1990

1992

1993

1994

0.33

0.56

1.24

2.80

0.77

0.81

•,

30

Nishimoto er aI. 1987

Beringer & Nishimoto 1988

Beringer & Nishimoto 1988

Beringer & Nishimoto 1988

this study

this study
Ln

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'=:t C\l 0 CD <C C\l .,.... .,.... .,.... •

S8>\EM!W)l J.O JaqwnN

Figure 9. Populationtrends of black-legged kittiwakes on plots at Gull Island, lower Cook Inlet, 1986-1994.

31

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•II1': Figure 10. Populationtrends of common murres on plots at Gull Island, lower Cook Inlet, 1986-1994.

.!~

I' 32

,.'

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II

•
Pigeon Guillemot

Populations.--We did not attempt to count pigeon guillemots at Gull Island in 1993. In 1994, the

maximum number oLadults seen was 13 on 30 June and I July. Because we scheduled our surveys to observe

mum'S when their numbers were most stable, and because pigeon guillemot activity patterns differ from' the

mum:s', our counts may have underestimated the size of the breeding population of guillemots at Gull Island. , .

Coums of pigeon guillemots at Gull Island included surveys directed spedfically to this species and peak annual

count:; ranged from 24 to 42 birds in the late 1980's (Nishimoto and Thomas 1991; Table 11). , .

60-foot Rock

Double-crested Cormorant

Populations.--No double-crested cormorants were observed on plots 'in 1993 or 1994. In fact, this

species has never been seen on the ledge-nesting seabird index plots since they were established in 1985 (Table

1). Nevertheless, we observed a nest that was not on one of the plots in mid-July 1993, and four roosting

adults were also seen in mid-August. This species was not observed on 60-foot Rock in 1994.

Productivitv,--One chick was seen on 20 July 1993 off the plots, but no information is available on a

fledging date. Few double-crested cormorants have used 60-foot Rock for breeding, but occasionally it is used

regularly by a few birds for roosting.

Pelagio Cormorant

Populations.--Few pelagic cormorants occurred on our ledge-nester plots (Table 1). Nevertheless, we

counted 45 birds and 39 nests on 60-foot Rock in 1993 (Appendix 1). In contrast, no birds nested on the rock

in 1994, but we counted 29 birds roosting there. Cormorants shift nesting locations periodically, so the change

among years may represent a shift to another nesting location. Indeed, counts at 50-foot Rock since 1976 have

been highly variable (Appendix I).

Productivitv.--Therewere .no active nests on plots in either year of the study, however, some nests

were observed off plots during island circumnavigations. Thiny-nine nests containing 29 chicks were observed

in are",; off our plots on 20 July 1993. If all these chicks fledged, .the productiVity rate would have been 0.74

chicks per active nest. As indicated above, no pelagic cormorants nested on 60-foot Rock in 1994.

Histori'oal data were not available for comparisons among years of breeding cormorants on 60-foot Rock.

However, productivity compared closely with nearby Gull Island (0.78) in,1993.

Glaucous-winged GuY

Populations.--Three replicate counts of plots on 60-foot Rock averaged 20 adults in 1993 and 17 in

1994 (Table 2). Whole-island counts of gulls indicated there may have been an increase between 1976 and

1986, but numbers remained relatively stable at between 80 and 113 birds through 1993 (Appendix 2). We

counted 60 adults on the island in 1994.

. Productivitv.--A maximum of 18 chicks was observed on 60-foot Rock during three replicate counts in

1993, while a maximum of six was seen in 1994. Because boat-based counts of this species yield only a gross

estimat<: of breeding performance, we could draw no conclusions about productivity except that gulls produced

some young in both 1993 and 1994.

33

•

•

•

•

•

•I

•

•

•

•

•
'j

·,1

•.:'

., ~. '''-- !"', ..lH- ... i-~ ..., . ,- ....

·'Table II. Pigeon guillemot counts in· lower Cook Inlet.

. I· ..$~,;.c"

Location Year I' Total •

.. I:

References

• maximum count in the pahicular year. number of nests in parentheses

60,foot Rock 1976 0 summarized in Nishimoto & Thomas 1991

1984

1985

1986 2(1)

1987 3

1988 no count

1989 0

1990 .3

1994 2 this study

~i"

i!

i'

•

Ij

•

•n.1

~!I

•

"'

.,

I'

•

Gull Island 1976

1984

1985

1986

1987

1988

1989

1990

1994

12

5

13

42

27

24

22

13

summarized in Nishimoto & Thomas 1991

this study

•

!i

I,"

•

34
Pige,m Guillemot

Populations.'-Pigeon guillemots have not been intensively monitored at 60-foot Rock, but counts were

usuaJJy completed as observers circumnavigated the island to survey ledge-nesting seabirds. We did not see any

guillemots during surveys in 1993, but two birds were noticed at 60-foot Rock in 1994. Historically, numbers

have been low. In 1986 two adults and one active crevice were noted (Nishimoto et al. i987). The highest

number of adults (6) on or adjacent to 6O-foot Rock was recorded in 1987 when more effon was given to search

for guillemots. In 1989, 1990, and 1994, two adult pigeon guillemots v.:ere noted each year near-60-foot Rock

(Nishimoto and Thomas 1991). . ,

Black-legged Kittiwake

Techniques identical to those used at Gull Island were used to study populations and productivity at 60-foot

Rock.

Populations.--About 65 black-legged kittiwakes used our index plots at 60-foot ~ock in 1993, and 103

was the mean count for 1994 (Table 3). In most years since 1986, approximately 100 bi~ds and 75 to 90 nests

have been present on the plots, but numbers were significantly lower in 1987 and 1993 (~'s < 0.1). Wholeisland counts since 1976 suggest there was a substantial increase between 1976 and 1984 (Appendix 3). It ,

appears the population at 60-foot Rock peaked during the period 1988-1990, and declined again to ·mid·1980s

levels by 1993-1994 (Fig. II, Appendix 3). .

Breeding Phenology.--We collected little information regarding breeding phenology at 60-foot Rock but

can grossly estimate when primary breeding events took place. In 1993 ~e observed six and ten hon-volent

young on 20 July and 17 August, respectively; one fledgling was seen during the last survey as well. In 1994

two non-volent young remained on plots by 17 August after four had be~n seen on 19 July. Phenology

appeared to be similar to that observed at Gull Island (Table 4). }

,

Productivity.--A mean of 47 nests was constructed by black-legged kittiwakes on 6O-foot Rock plots in

1993, and the mean was 89 in 1994 (Table 5). Although eggs and small 'chicks were not visible during

observations from the water,. older chicks could be counted. We did not 'observe any n~sts on 60-foot Rock that

contained more than one chick in either year of the study. Overall productivity was calculated to be 0.02 and

0.04 for 6O-foot Rock in 1993 and 1994, respectively (Table 5).

The kittiwake colony at 60-foot Rock consistently has lower productiVity than the colony at Gull Island (Table

5). At 6O:foot Rock, productivity has exceeded 0.2 young per nest in only two of eight breeding seasons for

which there are data since 1985 (Table 5). .

Common Murre

Populations.--The mean number of adult common murres attending plots on 60-foot Rock was 23 and

II, respectively for 1993 and 1994 (Table 6). Although the 1994 count \Vas the lowest recorded for the index

plots, there were no significant differences among years (p = 0.15, Table 6).

Whole,-island counts suggest there were mote murres at this small colony.in 1976 than in later years (Appendix

4). It is unclear whether there was ever a.stable breeding population here. CenainJy thete was little, if any,

nesting in 1993 and 1994, the population being composed primarily of roosting birds.

Flat Inlands

Durinl\ an island circumnavigation on I July 1993, we observed eight species of birds (Appendix 7).

35

,

I

I

I'

•

•

•

•

•

•

•

•

•

•

•
-S'(2~./ ~(2

~./ <9..

6"6"

C./

6"6"

.I ./

6"6"

a ./

1S16"

6'1./ <9.Ql./

<9&

Ql./

<&

Ql./

19& '- Ql./ ro

-S'& ~' Ql

./

(96"

el./ <9.

2'JQl./

<96"

.I ./

<96"./ 0& .

Ql./

6"<,:

6"./

<9<,:6"./

<<,:

•

6"./ 19~6" . -S'./

0 0<-

0 .' 6"./ .,.. o

o

C\I

••

o

o

(I')

•

o

o

"'f

•

o

o

l!)

•

•

()

o

a:

.....

o

'0

...

o

<0

i~

t

·.ii

I

:1

"t

I !

Ii·

ip

!'

ii

~.

Figure 11. populationtrends of black'legged kittiwakes on plots at 6O,foot Rock, lower . Cook Inlet, 197!i,1994. -

,36
Tufted Puffin

Populations.--During our survey of all habitats occupied by tufted puffms on I July 1993. we found

464 burrows on Flat Islands. of which 67% (312) were active. We were able to access'almost all areas along

the perimeter of the island. but a small number of burrows could have been overlooked. Furthermore.:i few

bUrlOWS could have occurred on inaccessible nearby islets (Fig. 4). We conservatively estimate that 500 tufted

bUrloWS were present in 1993. About 15% of the land area at Flat Islandswas used by nesting' tufted puffins.

Productiviry.--We marked all burrows found on the north half of Flat Islands in July for recheck in

August. In July. 74% of the burrows i~ the sample (n = 73) were active (i.e., probably had an egg). but only

61 % were active on 17 August. Taking the July occupancy rate as an index to the number of eggs laid, and the '

Aug:ust occupancy rate as an indication of the number of chicks, approximately 80 % of the burrows that had

egg'; in July had chicks in mid-August.

Byr,j et aI. (1993) reviewed 21 data sets of North Pacific tufted puffm colonies and found that, on average.

nearly 50 percent of the eggs produced fledglings. While recognizing ihe limitations of our indirect methods to

evaluate productivity, our result suggests productivity was nonnal or atiove this average at Flat Islands in 1993.

CONCLUSIONS

Om: of primaiy objectives of the study was to evaluate trends in seabird populations at lower Cook Inlet

bre"ding colonies (I.e., Chisik and Duck Islands, Gull Island, 60-foot Rock, and Flat Islands). Some of the

'species we monitored occurred at only one of the study areas while others occurred at" most. The following

conclusions were reached about various species:

1. Double-crested connorants appear to have declined since the early 1970s at Chisiklsland, the only

colony we surveyed where this species occurred in numbers. In contrast, there was no indication of a

decline over the past 20 years in pelagic connorant popularions at Chisik and Duck; Gull Island, or 60-

foot Rock.

2. Glaucous-winged gulls apparently increased or remained relatively stable at Chisik and Duck

Islands, Gull Island, and 60-fooi Rock between the mid-1970s and the early 1990s.

3. Black-legged kittiwake population trends varied among colonies. There was evidence of a slight

decline since the 1970s at Chisik and Duck Islands, but at Gu!1 Island and 60-foot Rock the popUlation

increased between the mid-1970s and the mid-1980s at which level it remained through the early 1990s.

•

•

•

•

•

•

•

;

4. Cornman murre numbers declined at Chisik and Duck Islands between 1970 and the mid-1980s, but

have remained stable since then. In cO;llr,;.i, numbers on GU(I Island have .increased since the mid1970s., The population of murres at 60-foOl Rock conta.ined few, if any, breeders in 1993 and 1994 so

numbers attending the colony were highly variable. It appears fewer birds were present in the early

1990s than in the 1970s. '

5. There were few prior counts of pigeonguillemots,'homed puffins or tufted puffms. so population

trends could not be critically assessed.

•

•

Be,;ides popularion trends. we exanrined timing of nesting events and reproductive sucCess for selected species,

particularly in 1993. Few prior data for Cook Inlet are ava.ilable. but.from what we could glean, it appeared

black-legged kittiwake laying dates were approximately nonnal, but mimes may have been slightly later than

normal.

37

•

•
Ii

.,

t'

,

.,

•

•

'.

;

•

•.,

In 1993 prey for seabirds may have been scarce near Chisik and Duck Islands, because cormorants, kittiwakes,

murres, and homed pUffin~ had relatively ,low. teproductive sucCesS:' FuMer down Cook Inlet in Kachemak

Bay, cormorants had lowel- than average success, and kittiwakes failed at 60·foot Rock but had limited success

at Gull Island, At the southernmost colony we monitored in Cook Inlet, Flat Islands, tufted puffins apparently

had good success in 1993'1 . .

The 1994 survey effort was reduced from 1993, but available data suggest reproductive success for kittiwakes

and murres was better in U994 than in 1993 at Chisik. At Gull Island, kittiwake productivity was better in 1994

than in 1993, but kittiwak~s failed to produce young at 60-foot Rock in 1994 just as they had in 1993,

ACKNOWLEDGEMENTS

Dr. David B. Irons coordinated this contract for the U.S. Fish and Wildlife Service and reviewed this

manuscript. Caretakers (Bbb and Dorea Woods, and Kirk and Carrie Soderlund) of the Snug Harbor Cannery

provided logistical supporl dUring our stayon Chisik Island. .

I

Special thanks go to Neil Herring and Dr. Joel Hubbard who conscientiously collected data, rendered

stimulating discussions, arid maintained an enjoyable field camp atmosphere. Many volunteers helped complete

colony counts: Terry Cartbn, Dave Erikson, Jane Kidd, Gary Montoya, George Powell, Sara Reinert, Lynda

and Anne-Marie Ronan, Kurt Schmidt, Kathy Smith, Arthur and Carol Westing, and Stephanie Zador. Richard

Lanctot contributed assista'nce in the field as well as invaluable review of the manuscript.

This study was funded in bart by the Department of Interior'in support of Minerals Management Service,

Alaska OCS Region, and the Environmental Studies Section. Opinions and conclusions found in this report are

based on research results hf the principal investigators and do not necessarily reflect the views of the MMS.

LITERATURE CITED

Andres, B.A. 1993. Potential impacts of oiled mussel beds on higher organisms: black oystercatchers.

Unpubl. rep., U.'S. Fish and Wildl. Servo Anchorage, AK.

Beringer, B. and M. NisJimoto. 1988. The status of breeding seabirds at Chisik and Duck Islands during the

summer of 1987.1 Unpubl. rep., U.S. Fish andWildi. Serv., Alaska Maritime Natl. Wildl. Refuge,

Homer, AK. 12 ~p. + appendix. .

Byrd, G.V. 1989. seabirds in the Pribiloflslands, Alaska: trends and monitoring methOdS~ M. S. Thesis,

Univ. of Idaho. 196 pp.

Byrd, G.V., E.C. Murphy, G.W. Kaiser, A.Y. Kondratyev, and Y.V. Shibaev. 1993. Status and ecology of

offshore fish-feeding alcids (murres and puffms) in the North Pacific. In The Slatus, ecology, and

conservation of kmne birds of the North Pacific. Vermeer, K., K.T. Briggs, K,H. Morgan, and D.

Siegel-Causey (e\is.). Can. Wildl. Servo Spec. Publ., Ottawa.

Dragoo, D.E., RK..BaiL M.J.-Melendez, and C.M. Minch. 1991. Changes in colony size and reproductive

success of seabifds at the Semidi Islands, Alaska, 1976-1991. Unpubl. rep., U.S. Fish and Wildl.

Serv., Alaska M'aritime Natl. Wildl.Refuge, Homer, AK. 43 pp.

Dragoo, B.K. and K. sJdSeth. 1993. The status of northern fulmars, kittiwakes, and murres at SI. George

Island, Alaska, In 1992. Unpubl. rep., U.S. Fish and Wildl. Serv., Homer, AK. 19 pp. + figures, , .

tables, and appendices.

38
Erikl;on, D. 1976. Distribution, abundance, migration and breeding lo,ations of marine birds in lower Cook

Inlet, Alaska. Vol. 8. In Trasky, L.L., L.B. Flagg and D.C. Burbank, eds. Environmental studies of

Kachemak Bay and lower Cook Inlet. Unpubl. admin. rep., AK. Dep. Fish and Game, Marine/Coastal

Habitat Manage. Anchorage.

Eribon, D. 1993. Surveys of murre colony attendance in the nonber Gulf of Alaska follOWing the £r:xon

Valdez oil spill. Presentation at the Third ASTM symposium on Environment, Toxicology, and Risk

Assessment; Aquatic, Plant, and Terrestrial, April 25-28, 1993, Atlanta, GA.

Gabrielson, I. and F. Lincoln. 1959. The Birds of Alaska. The Wildlife Management Institute. Stackpole

Press..

Jonel;, R.D. and M.R. Petersen. 1979. The pelagic birds of Tuxedni Wilderness, Alaska. Unpubl. rep .. U.S.

Fish and Wildl. Serv., Biological Servo Prog., Anchorage, AK. 41 pp.

Janel', R.D., M.R. Petersen, C. Slater and J. Burke-Ogan. 1980. The pelagic birds of Chisik and Duck

Islands. Final repon. U.S. Fish and Wildl. Serv., Biological Servo Prog., Anchorage, AK. 33 pp.

Kafka, D.M. 1984. Kittiwake productivity on Chisik and Duck Islands, .Cook Inlet, Alaska. Unpubl. rep.,

Univ. of AK., Fairbanks. 14 pp.

Krohn, W.B. .1966. A brief survey of the Tuxedni National Wildlife Refuge. Unpubl. rep:, U.S. Bur. Spon

Fisheries. Kenai, AK. 12 pp.

Mendenhall, V.M., D.E. Dragoo, L. Haggblom and E.C. Murphy. 1991. Chapter II. Monitoring of

populations and productivity of seabirds at St. George Island, Cape Peirce, and Bluff, Alaska, 1989.

Rep. by U.S. Fish and Wild!. Serv., Anchorage, AK., to Minerals Manage. Servo No. 90-0049,

Anchorage, AK.

Moe.. R.A. and R.H. Day. 1977. Populations and ecology of seabirds of the Koniuji Group, Shumagin

Islands, Alaska. In Population dynamics and trophic relationships of marine birds in the Gulf of Alaska

and southern Bering Sea. .Pan VI. Office of BioI. Serv.lCoastal Ecosystems, U.S. Fish and Wildl.

Serv., Anchorage, AK. 85 pp..

Muhlberg, G. 1984. Chisik and Duck Islands repon (draft). Unpubl. rep., U.S. Fish and Wildl. Serv.,

Anchorage, AK.

Murie,O.J. 1959. Fauna of the Aleutian Islands and Alaska Peninsula. Nonh Am. Fauna, Number 61, Dep.

of the Interior. Washington, D.C. 406 pp.

Nishimoto, M. and B. Beringer. 1989. Breeding seabirds at Gull Island and 60-foot Rock during 1987-88.

Unpubl. admin. rep., U.S. Fish and Wildl. Serv., Homer, AK.. 24 pp. + appendices.

Nishimoto, M. and B. Beringer. 1990. Breeding seabirds at Gull Island and 6O-foot Rock during 1989.

Unpubi. admin. rep., U.S. Fish and Wildl. Serv., Homer, AK.

Nishimoto, M" D. Debinski, K. Rose and K. ZThounhurst. 1987. Breeding seabirds at Gull Island and

6O-foot Rock during 1984-86. Unpubl. admin. rep., U.S. Fish and Wildl. Serv., Homer, AK. 19 pp.

+ appendices.

. 39

•

•

•

•

•

•

•

•

•

•

•
II

I

"

ij

.,

I

t

"

'I'·ry

I

I!'

I

riii

Ii'

ij,

I.

t

, . .. ' .

Nishimoto, M. and C. Th?mas. 1991. Breeciing seabirds at Gull Island and 60-foot Rock during 1990.

Unpubl. rep., U.S. Fish and WildI.SeiV.,Homer, AK. '24 pp. +"appendices.

Sanger, G. and M. COdY'! 1994. Surveys of pigeon guillemot colomes III Prince William Sound, Alaska

Exxon Valdez Final Resroranon Rep. 93-034.

sn~ski, D.A. 1970. KJWake ecology, Tuxedni Nanonal Wildlife Refuge. Alaska Coop. Wildl. Res. Umt . I

Quarterly Rep. July-September 22: 10-13.

Snarski, D.A. 1971a. KiltiWake ecology, Tuxedni National Wildlife Refuge. Alaska Coop. Wildl. Res. Unit.

I

Quarterly Rep. JTY-September 21: 6-8. '. • .

Snarski, D;A. 1971b. Kittiwake ecology, Tuxedni National Wildlife Refuge. Alaska Coop. Wildl. Res. Unit. , Quarterly Prog. Rep. Jan-March 22: 15-23. .

Snarski, D.A. 1971c. slbird colonvdatasheet for Tuxedni National Wildlife Refuge. Unpublished:

Snarski. D.A. 1974. SOIL aspects ~f ~e ecology of the black-legged kittiwake during two years of nesting

failure. Univ. Alkka., Coop. Wildl. Research Unit, Fairbanks. Thesis manuscript. 38 pp.

SOWlS: A.L., s.A.Hatch.land C.1. Lensink. 1978. Catalog of Alaskan seabird colonies U.S. Fish and

Wildlife Service FWS/OBS - 78/78. Washington, D.C.

I . , Sowls, A.L. 1985. Seabird colony catalog update. Unpubl. computer printouts, U.S. Fish and Wildl. Serv.,

Anchorage, AK.

. "

40
••••••••

42

,F

••••••
1

I

I

I

,

,j'•

, , .p-

. .

Kafka'1984,., ',' y

Nishimoto, unpublished data

Nishimoto 1987 ,~ ",:"

this study

Murie 1959

,.....

:~~ .'

1936,.- .25',000

1970, 20,000

1971 47,690

1978w 28,000

1979 28,000

1983' 20,000

1985 '18,170

1986",~ , ,27,228,

1993"1' " .HI;19L,',: ",

1994' 17,804

) -,

Chisik Island '

,rr-- 7','W

i,!·, II ., .' .

..- "~ .

""¥ -,

1 App'end~x .3. ,su~arY£1 black~legged ki~tl;.~;<poPulation estimat~s,i~~e,~~cted lower Cook Inlet colonies: , \~~~:'~

,_LO-,ca'-.t~io:.:n:,.::::.;;_:.:Y:.:e.::ar:....,,,-+-1_E:.s:.:':.:im.::a::.t:.:e;:;.i::::.,'-.,':;!""'-'..:S:.:o.:u;..rc:.:e_-' -'::::":..',:.;i::.;-~_C:.o:.:mm=:.:e.::n.::ts-' __-,:....,,-- t;.. 'J..:

1

.mayinclude,only the SW 'colony t

, i Snarski'197Ia

"~,..countedliirearly AuguSt

Jonesiand,Peterson ,1979

Jones et,al, 1980 ",:-

, estimate'of "Tuxedni -Bav area" /.; .~~ . 'counted, prior to nest 'building

1(".~':~ : (""'l

. ": t( ;::...r:',.,.

,

, ,

(, \- :~ . •

j

J.-..• ~\

,'

, .

, ,

'-::O:1U

:rl-,!>'-i,

,.

lJ\·'~ r

:"'~~'.

;"':lN~

o;.j~~

()tf.

~r:::

t.'

.',

. '-c-, . _.....

W" 11(, '1h"

Nishimoto & Beringer,1989

Nishimoto & Thomas 1991 '

. ~-;~ ... rt~l ", r·:c->t't·,e~'l'

this study

Erikson 1976

Nishimotoet ai, 1987 ,'-111,:

NishiiDl?to:~~Thomas' 1991:

tr,. . ,,,.~ '"'!.:, -!J:" .,..' -:~~~"'l .t'I~

}._\-. ';; "~

Erikson-,J976', '! b- ,':" "

Nishimoto etal,l1987 - .'-" -.

.

68

(199)

(177)

289

250

414

351

391

186

294

3194

(4204) ,

8202

6986(5684), '

·tfL'" •

1976

1984

1985

''I ,,, 1990 cA i~ f~ .....,l._,

l!J;'.L..{· .....l i , ........ ~l:..-'-. • .... 'n

l.lfttl.t., . .

1976 t.:-=.~~._ .~ ..' ,,~ .. 1984

1985

1986

1987

1988

1989

1990

1993

1994

Gull Island

• estimate is the mean of daunts pooled for plots; numbers of nesisare',io parentheses'"

, inbludes Duck Island " , .' ,

60,foot Rock

:-:"

,.:~ . ,.

Ii: i

j," f ,I; i

';1 ,- I

I

I

f

;1

r

f,'

f,i

f

;;'J

:i:

.~:.

..J

( i

,

I

f •

t

I

r

i: t

,

I

, I" 

--
t61

i

,.

<1

<1

.·1 '.J i ."~ !!.

.,

... -.,-

64.'i~

60

52

52

114

56

40

109

95

85

118

114

131.

60

70

67

64

65

69

64

62

65

75

63

63

74

65

107

143

108

111

61

'61 ' ,.

'92'

120

145+

65

70

65

51

-65

..... ...

"

.;,

; ..

., '~

..,. ;.......... .-;..~~.'..;.:-;.':..:'~ . _.._ -_·~:t~-<~-'.--,::~":"".:·~-:",:_··· _, _ ~~

-:.Sampl~, # !":'~'Sampli~g ,Meth"d • '., ,~Spec~es .'[), Tota( Le~gth~inm). Mass(gm) ,,-:_..- '~·h j'~ ) ·1

.:x. §pp(,:~ :....-·10 l,(f. sand 1

1ance j

screen .'.' _. ;>'. ~and.lance I

screen' .....:::.':;..'.;;"; ,sand-Jance

.screen i"+Y; ,.;,;U ,,{ s~~l~ce I

streen 1"" sand"lance. ,[ ~r ~i?! . opport f .~, sand lance!

apport sandlance!

screen sand lance f

screen sand.lance 'f:':'"1 .0' 1 •.

opport " ~'''' ;, :"sand l:mce

screen f~~-;' t sand··lance

screen sand lance'

opport , .. _" .. sand Iance . .J _. ~~ " '.', " .,~

opport, .. , ,~, .' '. . sand lance .......? ,'. ,~~ -"~~ll-;-".-,... --_i;,j; ...........,.....,.• -... ,,-&<

opport sand lance

apport !,'\..,~-c'~~ . ~ "'-9~. sand lance

opport sand lance

opport, I, j 'l :. " sand lance

opport . y,.' {.;, : sand.lance

opport ' inlknown

opport unknown

apport i.- "j- . '""...,, i: -l~9wn;

opport unknown

. opport '" '.,., ,> 1,sll;1ld lance,

opport sand lance

screen sand lance .screen ~i""'''d' s~d lance

·opport .. ~.. - ~Sand ,lance

::-...."",~5reen ~~ .sand lance

screen sand lance

screen sand lance

screen sand lance

screen sand lance

screen sand lance

screen sand lance

screen sand lance'

screen sand lance I

screen sand lan,cel

screen ~nknown

screen sand lance I,

,screen sand lance •

,'-." . •

i

I

i

!

I

~: ".!,," ," ": -~'.: .' .')' .... , .,.. ...•. . ·i. . .'

Diet samples broilghtto hornei:l'puffmchicks1at Duck'!sland,1'i\laska: in 1~93,:-','

.~ '" ~.' """., ~,..' "" -,.-... '. ·1·:·

, "

f"';.... -:;::::._~" -~'~''''~

07 August

"J -l

2a i

· ·2b

~" , , ,2c

",,,:, 2d

"a

, ,'3

4a

, .1, 4b , 5

6a

... 6b

'._ 7a

7b '';-10' ,7.-~·""'"'--~""''". ,

i"l7d

· 7e

,--.:,7f

,7g

· 4;~8a

'" 8b8c

'.',.9a

9b

'" 9c

lOa J'

lOb

09 August·:, :' 11 ..

-l '~'_'T .~,. ~~ .t.f. < ~'~.i, ~~a

~i" '_, 12b

12c

12d

12e

12f

12g

12h

121

12j

12k

13a

13b

06 August

Date ,Collected,' • ,••,. _.' _ • --'-J..-l- '.

:-. '~.;: "l!:~.

App,:hi:lix 6,

03 August

4 August

01 August

...-'"

!

I

L~'
6,5

7

16a screen sand lance 124

16b screen sand lance

17 screen sand lance 139

18 opport sand lance 75

19a screen unknown 104

19b screen sand lance 60

19c screen sand lance 92

19d screen sand lance 80

1ge screen sand lance 70

19f screen sand lance 56

199 screen sand lance 86

19h screen sand lance 79

191 screen sand lance 70

19j screen , unknown 70

19k screen sand lance 67

191 screen sand lance 65

19m screen sand lance 62

19n screen sand lance 67

,

10 August

• opport= samples cOllectk opportunistically at burrow entrances that may not comprise a complete bill load

b Ammody/es hemp/erus

Appendix 6. Continued.

."~

\,

~amPlle # • Date Collected Sampling Method' ' Species Total Length(mrnl Mass(gm) ,

09 August 13c screen sand lance 94

13d screen sand lance 82

13e scr~en sand lance 80

13f screen sand lance 88 I

13g screen sand lance 97

13h screen sand lance 104

13i screen sand lance 92

14 opport sand lance 148

15 screen sand lance 86

~:

It,,'

'I' ,I

..

:1

It

ii-

!I!-

!I:

II'

!~

'"

't!B,

It

47

It
------- --c--------------------------------------------

,

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App',ndix 7, Wildlife recorded during a circumnavigation of Flat Islands, Kachemak Bay, Alaska, I July 1993.

Species

Double-crested cormorant

Nonhern pintail

." Black oystercatcher

,

. Glaucous-winged gull

'Number of

individuals

2

2

2

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.Pigeon guillemot

Tufted puffm

Bank swallow

:Song sparrow

Steller sea lion

.. -15

20

50

4

3

48

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