Monitoring Results for 

Breeding American 

Peregrine Falcons (Falco 

peregrinus anatum), 2003

Biological Technical Publication 

BTP-R1005-2006

U.S. Fish & Wildlife Service

Ted Swem, Region 7, USFWS

Monitoring Results for 

Breeding American 

Peregrine Falcons (Falco 

peregrinus anatum), 2003

Biological Technical Publication 

BTP-R1005-2006

U.S. Fish & Wildlife Service

Michael Green1, Ted Swem2, Marie Morin3,11, Robert Mesta4, 

Mary Klee5, Kathy Hollar6, Rob Hazlewood7,12, Phil Delphey8, 

Robert Currie9, Michael Amaral10

1 U.S. Fish and Wildlife Service, Region 1, Division of Migratory Birds and 

Habitat Programs, Portland, OR Michael_green@fws.gov

2

 U.S. Fish and Wildlife Service, Region 7, Ecological Services, Fairbanks, AK

3

 U.S. Fish and Wildlife Service, Region 1, Ecological Services, Portland, OR

4

 Sonoran Joint Venture, Tucson, AZ

5

 U.S. Fish and Wildlife Service, Region 9, Ecological Services, Arlington, VA

6

 U.S. Fish and Wildlife Service, Region 1, Ecological Services, Portland, OR

7

 U.S. Fish and Wildlife Service, Region 6, Ecological Services, Helena, MT

8

 U.S. Fish and Wildlife Service, Region 3, Ecological Services, Bloomington, MN

9

 U.S. Fish and Wildlife Service, Region 4, Ecological Services, Asheville, NC

10 U.S. Fish and Wildlife Service, Region 5, Ecological Services, Concord, NH

11 Current address: 4920 SE 140th Ave, Portland, OR 97236

12 Current address: P.O. Box 4322, Helena, MT 59604
ii Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

Author Contact information:

Michael Green, U.S. Fish and Wildlife Service, 

Region 1, Migratory Birds and Habitat Programs, 

911 N.E. 11th Ave., Portland, OR 97232-4181. 

Phone: (503) 872-2707, Fax: (503) 231-2019, E-mail: 

Michael_Green@fws.gov

Ted Swem, U.S. Fish and Wildlife Service, Fairbanks 

Fish and Wildlife Office, 101 12th Ave., Box 19, 

Fairbanks, Alaska 99501. Phone: (907) 456-0441, 

Fax: (907) 456-0208, E-mail: Ted_Swem@fws.gov.

Marie Morin (Current address), 4920 SE 140th Ave, 

Portland, Oregon 97236. marie_p_morin@hotmail.

com

Robert Mesta, Coordinator, Sonoran Joint Venture, 

738 N. Fifth Ave. Suite 215, Tucson, Arizona 85705. 

Phone: (520) 882-0047, Fax: (520) 882-0370, E-mail: 

Robert_Mesta@fws.gov.

Mary Klee, U.S. Fish and Wildlife Service, Division 

of Habitat Conservation Plans, Recovery, and State 

Grants, 4401 N. Fairfax Dr., Mail Stop 420 Arlington 

Square, Arlington, VA 22203. Phone: (703) 358-2061, 

Fax: (703) 358-1735, E-mail: Mary_Klee@fws.gov.

Kathy Hollar, U.S. Fish and Wildlife Service, Region 

1, Division of Endangered Species, 911 N.E. 11th 

Ave., Portland, OR 97232-4181. Phone: (503) 231-

2359, Fax: (503) 231-6243, E-mail: Kathy_Hollar@

fws.gov.

Robert Hazlewood (Current address), P.O. Box 4322, 

Helena, MT 59604. Tierra1@theglobal.net

Phil Delphey, U.S. Fish and Wildlife Service, 

Ecological Services, Twin Cities Field Office, 4101 

E. 80th St., Bloomington, Minnesota 55425. Phone: 

(612) 725-3548, Fax: (612) 725-3609. E-mail: Phil_

Delphey@fws.gov.

Robert Currie, U.S. Fish and Wildlife Service, 

Ecological Services, Asheville Field Office, 160 

Zillicoa St., Asheville, North Carolina 28801. Phone: 

(828) 258-3939, Fax: (828) 258-5330. E-mail: Robert_

Currie@fws.gov.

Michael Amaral, U.S. Fish and Wildlife Service, 

Region 5, Ecological Services, New England Field 

Office, 70 Commercial St., Ste. 300, Concord, New 

Hampshire 03301-4986. Phone: (603) 223-2541, Fax: 

(603) 223-0104, e-mail: Michael_Amaral@fws.gov.

For additional copies or information, contact:

Migratory Birds and Habitat Programs

U.S. Fish and Wildlife Service

911 NE 11th Ave

Portland, OR 97232

Recommended citation:

Green, M.G., T. Swem, M. Morin, R. Mesta, M. Klee, 

K. Hollar, R. Hazlewood, P. Delphey, R. Currie, and 

M. Amaral. 2006. Monitoring results for breeding 

American Peregrine Falcon (Falco peregrinus 

anatum), 2003. U.S. Department of Interior, 

Fish and Wildlife Service, Biological Technical 

Publication FWS/BTP-R1005-2006, Washington DC.

Series Senior Technical Editor:

Stephanie L. Jones

USFWS, Region 6

Nongame Migratory Bird Coordinator

P.O. Box 25486

Denver Federal Center

Denver, Colorado 80225-0486
iii

Table of Contents

List of Figures .................................................................................................................. iv

List of Tables..................................................................................................................... v

Acknowledgments ............................................................................................................ vi

Summary ......................................................................................................................... 1

Introduction...................................................................................................................... 2

Methods.......................................................................................................................... 3

Monitoring Regions............................................................................................................ 3

Sample Size Determination .................................................................................................. 3

Monitoring Protocol ........................................................................................................... 3

Analyses ......................................................................................................................... 4

Results ........................................................................................................................... 5

Discussion ....................................................................................................................... 9

Conclusion......................................................................................................................10

Literature Cited.................................................................................................................11

Appendix A: List of Data Collectors by Monitoring Region and State..................................................13

Appendix B: Sample Peregrine Falcon Monitoring Form ................................................................15

Appendix C: Monitoring Data ................................................................................................16
iv Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

List of Figures

Figure 1.......................................................................................................................... 4

Figure 2.......................................................................................................................... 7

Figure 3.......................................................................................................................... 8
List of Tables

Table 1: Territory and nest data, American Peregrine Falcon, 2003................................................... 5

Table 2: Territory occupancy, nest success, and productivity for the American Peregrine Falcon, 2003. ....... 6

Table 3: 2003 continental population estimate, American Peregrine Falcon. ........................................ 6

Table 4: Numbers of nest sites on natural versus manmade substrates, American Peregrine Falcon, 2003.... 8

Table C-1: Monitoring Data .................................................................................................16
vi Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

Acknowledgments

The monitoring team is especially grateful to Bob 

Steidl for his statistical guidance. However, we 

would have no data to analyze were it not for more 

than 300 observers, volunteers and paid personnel, 

who ventured into the field in 2003 at least two 

and sometimes many more times over a three to 

four month period to observe Peregrine Falcons. 

Territory accessibility ranged from roadside to 

remote; the latter requiring hiking, rafting, or access 

by air. This nation-wide monitoring effort by the U.S. 

Fish and Wildlife Service is completely dependent 

on the network of State and Federal agencies, 

Tribes, and many other organizations that marshal 

this cadre of dedicated observers, annually in many 

States or regions. The observers themselves, united 

by their collective dedication to Peregrine Falcons, 

might not be aware of the larger network to which 

they belong. We know that Appendix A fails to list all 

participants and apologize to those overlooked. We 

hope this list gives some perspective on the number 

of people involved.

Funding for this effort was provided to States and 

other cooperators by the U.S. Fish and Wildlife 

Service. Thanks to George Allen, Brad Bortner, 

Susan Earnst, Suzanne Fellows, Stephanie L. Jones, 

Bob Steidl, and Tara Zimmerman for reviewing 

earlier versions of this report.


Summary

In 2003, the U.S. Fish and Wildlife Service 

(Service) implemented the first of five nationwide 

monitoring efforts for American Peregrine Falcons 

(Falco peregrinus anatum) (Peregrine Falcons) as 

described in the Service’s post-delisting monitoring 

plan (USFWS 2003). More than 300 observers 

monitored 438 Peregrine Falcon territories 

across six monitoring regions. Monitoring in the 

Southwestern monitoring region fell short of 

the monitoring goal, where 36 of the targeted 96 

territories were monitored; efforts are underway 

to implement full-scale monitoring in that region in 

2006. The five other monitoring regions surveyed 

sufficient territories to meet the statistical criteria 

described in the post-delisting monitoring plan. 

Our estimates of territory occupancy, nest success, 

and productivity were above the target values that 

we set in the monitoring plan for those nesting 

parameters. Additional data collected by this effort 

documented that the total number of nesting pairs of 

Peregrine Falcons is estimated at 3,005. Additional 

data show that 92% of pairs nest on natural 

substrates in all regions except the Midwestern/

Northeastern region, where only 32% nest on 

natural substrates. Our estimates of the nesting 

parameters and the additional data from across the 

United States indicate that the Peregrine Falcon 

population is secure and vital. The next coordinated 

nationwide monitoring effort is scheduled for 2006 

(USFWS 2003).
Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

Introduction

The history of Peregrine Falcons in the United 

States, their population decline caused by 

environmental contaminants and their recovery 

following bans on those chemicals, is a tale of 

conservation success. By the late 1960’s Peregrine 

Falcons had disappeared from the eastern United 

States and Midwest and were substantially reduced 

in the Western United States, Canada, and Mexico 

(Kiff 1988, Enderson et al. 1995). The Service 

officially listed Peregrine Falcons as endangered in 

1970 under the Endangered Species Conservation 

Act of 1969, a precursor of the Endangered Species 

Act (ESA) of 1973 (for a history of listing actions 

see USFWS 1999) and set recovery goals based 

on abundance and productivity in four regions of 

the United States. In some of these regions it also 

established goals for reduced contaminant effects 

(USFWS 1982a, 1982b, 1984, 1991, 1993; Figure 1). 

By 1999, recovery goals had been almost completely 

met in all regions, primarily due to a ban on the use 

of DDT and other chlorinated hydrocarbons and to 

the successful captive breeding, rearing, and release 

of over 6,000 Peregrine Falcons (White et al. 2002). 

Peregrine Falcons were removed from the Service’s 

List of Threatened and Endangered Species on 

August 25, 1999 (USFWS 1999).

From 1999 to 2003 the Service developed a postdelisting monitoring plan (USFWS 2003) for 

Peregrine Falcons in cooperation with other Federal 

and State agencies, Tribes, and nongovernmental 

organizations (USFWS 2003). This plan is designed 

to detect a significant decline in territory occupancy, 

nest success, or productivity in six monitoring 

regions across the United States. These three 

indices of population health were low between 

1950 and 1980 when Peregrine Falcon populations 

declined severely; the three measures then 

rebounded during population recovery (Cade et al. 

1988, Enderson et al. 1995, USFWS 1999, White 

et al. 2002). The monitoring plan (USFWS 2003) 

calls for monitoring every three years beginning 

in 2003 and ending in 2015. These five monitoring 

periods meet the requirement of ESA (to monitor 

“. . . for not less than five years . . .”) and the threeyear interval spreads the monitoring over 13 years, 

reflecting the concern of the Service for the longterm future of Peregrine Falcon populations. The 

monitoring plan is also designed to collect baseline 

information on contaminant loads in each monitoring 

region through the annual collection and archiving 

of addled eggs and feather samples. Those samples 

will be analyzed and reported in future years. 

This report is of results from Peregrine Falcon 

monitoring in 2003, which yielded data on territory 

occupancy, nest success, and productivity from 

across the United States. This is the first report 

of post-delisting monitoring results for Peregrine 

Falcons.
Methods

Monitoring Regions

The six monitoring regions are: Pacific, Rocky 

Mountain/Great Plains, Southwestern, Midwestern/

Northeastern, Southeastern, and Interior Alaska 

(Figure 1). The monitoring region boundaries 

conform to the Service’s regional divisions with 

the exception that Service regions 3 (Great Lakes 

and Big Rivers) and 5 (Northeast) are combined 

into a single monitoring region. These monitoring 

regions are similar to the original four Peregrine 

Falcon recovery regions, with some minor boundary 

adjustments (USFWS 2003).

Sample Size Determination

In each of the Pacific, Southwestern, Rocky 

Mountain/Great Plains, and MidwesternNortheastern monitoring regions, we randomly 

selected 96 territories from the set of territories 

occupied at least once from 1999 through 2002. 

This is the estimated sample size required to 

detect a decline in nest success from 68% (average 

nationwide nest success from 1999-2002) to 55% 

(potentially indicating an unhealthy population) 

with a type I error (alpha) of 0.1, and a type II error 

(beta) less than or equal to 0.2; the statistical power 

to detect declines of that magnitude is thus greater 

than or equal to 0.80 (1–beta), or 80% (USFWS 

2003). In this effort, power measures the ability 

of our sampling of the population to accurately 

reveal the 13 percentage point decline of interest; 

beta indicates the probability of making a type II 

statistical error, that is, of incorrectly accepting 

the null hypothesis that nest success or territory 

occupancy did not fall by 13 points, when in fact it 

did. The calculated number of adequately monitored 

occupied territories to achieve these statistical 

criteria is 67. The sample size calculation of 96 

territories accounts for the fact that Peregrine 

Falcons occupy about 75% of monitored territories in 

any year, and a margin of error of 7 (10%) territories 

per monitoring region to ensure that a sufficient 

number of nests are monitored. If the initial random 

selection of territories included a territory that was 

too difficult to monitor adequately, usually because 

of inaccessibility, then we randomly selected an 

alternate from the same pool of territories from the 

same State. Although this introduces a potential 

bias to territory selection, we considered it a 

reasonable way to maintain a sufficient sample in the 

face of practical considerations of monitoring. Six 

territories were reselected in this way in 2003.

In the Southeastern Region all known territories 

(n = 21) were monitored. In Interior Alaska, we 

monitored all territories (n = 100) along portions of 

both the Tanana and Yukon rivers, mostly by boat; 

these remote stretches of river have been monitored 

in this way for 20 years, and thus we took advantage 

of established protocols and manpower to determine 

the health of Peregrine Falcons in Interior Alaska.

Monitoring Protocol

Peregrine Falcon nest sites were observed by 

volunteers, agency personnel and other partners 

(Appendix A). Observers reported data to regional 

coordinators on a data collection form (Appendix B), 

who then consolidated the regional monitoring data 

and sent it to the national coordinator for analysis.

Observers visited each randomly selected territory 

to determine occupancy, nest success, and 

productivity. Observers were instructed to maintain 

sufficient distance from nests so as not to elicit 

sustained territorial behavior from either adult 

(Pagel 1992). Occupied territories were those where 

either a pair of Peregrine Falcons was present (two 

adults or an adult/subadult mixed pair) or there was 

evidence of reproduction (e.g., one adult is observed 

sitting low in the nest, eggs or young are seen, 

or food is delivered into eyrie). Territories were 

considered unoccupied if the above criteria were 

not met after the territory was visited during two 

observer visits of four or more hours each during the 

appropriate months (USFWS 2003). The calculation 

of territory occupancy is the number of occupied 

territories divided by the number of territories that 

were monitored.

Nest success is the percentage of occupied 

territories in a monitoring region with one or more 

young ≥ 28 days old, with age determined following 

guidelines in Cade et al. (1996). Productivity is the 

number of young observed at ≥ 28 days old per 

occupied territory averaged across a monitoring 

region (USFWS 2003). Most counts were made 

of young 28 days old to fledging age (ca. 45 days 

post-hatch). However, some observers reported the 

number of young fledged based on visits conducted 

immediately after fledging. These data were used 

if they were the only counts of young ≥ 28 days old 

from that territory. In Interior Alaska, productivity 

is estimated from observations made during the 

final transect, regardless of nestling age, although 

average nestling age is usually between 14 and 

28 days.
 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

Some States, Service regions, and private programs 

monitored all known Peregrine Falcon nesting 

territories, not just those selected as part of this 

monitoring effort. Data from these efforts are also 

summarized here.

Analyses

We compared territory occupancy, nest success, 

and their 90% confidence intervals, to target values 

derived from nationwide data collected from 1999 

through 2002 (Steidl et al. 1997). These target values 

are 84% (90% CI = ± 2%) territory occupancy 

and 68% (90% CI = ± 2%) nest success (USFWS 

2003). We also compared the estimates of territory 

occupancy and nest success and their confidence 

intervals to “. . . thresholds for agency response . . .” 

13 percentage points lower than the target values. 

The thresholds are 71% for territory occupancy 

and 55% for nest success (USFWS 2003). We 

compared estimates of productivity and their 90% 

confidence limits to a threshold value of 1.0 nestling 

per occupied territory; historic, and contemporary 

productivity; and to estimates of this parameter 

in Peregrine Falcon population models (USFWS 

2003). We used the finite population correction in our 

calculations of confidence intervals around estimates 

of territory occupancy, nest success, and productivity 

(Scheaffer et al. 1996). The finite population 

correction requires knowledge of the overall 

population size. For Peregrine Falcons, we are fairly 

confident in our estimate of overall population size in 

each region. Regardless, we made the conservative 

assumption that the total nesting population was 

10% larger in each region than is currently known, 

perhaps more likely in Western than in Midwestern, 

Eastern, or Southern regions.

Figure 1: Monitoring and recovery regions for the American Peregrine Falcon, 2003. Service Region 

boundaries outlined in each map—Region 1 (Pacific, excluding Hawaii and other Pacific Islands); 

R2 (Southwest); R3 (Great Lakes-Big Rivers); R4 (Southeast, excluding Puerto Rico & Virgin Islands); 

R5 (Northeast); R6 (Mountain-Prairie); R7 (Alaska).

Monitoring Regions

Pacific

Southwestern

Midwestern/Northeastern

Southeastern

Rocky Mountain/Great Plains

Interior Alaska

Recovery Regions

Pacific

Eastern

Rocky Mountain/Southwestern

Alaska


Results

Across the nation, 438 Peregrine Falcon territories 

were monitored (Table 1; Appendix C): 36 in the 

Southwestern Region (New Mexico and Big Bend 

National Park, TX); 21 in the Southeastern Region; 

100 in Interior Alaska; 96 in the Pacific Region; 95 

in the Midwestern/Northeastern Region; and 90 

in the Rocky Mountain/Great Plains Region. Some 

territories were incompletely monitored and were 

omitted from further analysis. Regardless, sample 

sizes were sufficient to achieve the statistical targets 

of the monitoring plan for all monitoring regions 

except the Southwestern Region (Table 1). In the 

Southwestern Region, the power to detect 13 point 

declines in nest success and territory occupancy 

dropped to 53% and 63%, respectively, due to limited 

sample sizes.

Estimates of territory occupancy varied from 78% 

to 95% across regions and averaged 87% for the 

nation (Table 2). Ninety percent confidence intervals 

around their means included or exceeded the target 

value of 84% (Figure 2). In the Southwestern Region 

the estimated territory occupancy was 78%; the 

90% confidence interval (67% to 89%) included 

the threshold for Service response for territory 

occupancy, which is 71%, 13 points lower than the 

target of 84% (USFWS 2003).

Estimates of nest success ranged from 64% to 78% 

across regions and averaged 71% for the nation 

(Table 2). Ninety percent confidence limits around 

nest success means included or exceeded the 68% 

target value, and were all above the threshold for 

agency response (Figure 2).

Estimates of productivity varied from 1.45–2.09 

across regions and averaged 1.64 for the nation 

(Table 2), and 90% confidence intervals exceeded the 

threshold for agency response of 1.0 (Figure 2).

In the Southeastern Region observers monitor 

every known territory. Thus, the summarized 

data from this region likely represent true values 

for southeastern Peregrine Falcons rather than 

estimates of those values as in other regions. 

Nevertheless, we assumed there are a few 

territories that have not been discovered and thus 

also show confidence intervals around the ‘estimates’ 

of the population parameters in the Southeast.

Data beyond that requested in the Monitoring Plan 

were reported by States or monitoring regions, 

including the number of newly discovered territories 

in 2003, updated counts of occupied territories, and 

the number of pairs using manmade structures 

Table 1: Territory and nest data, American Peregrine Falcon, 2003.

Region

Territories 

Checked

Territories Occupied 

(known outcome)1

Successful 

Nests2

Number of 

Young3

Pacific 96 80 (75) 49 109

Southwestern 36 28 (26) 20 45

Midwestern/Northeastern 95 86 (82) 62 171

Southeastern 21 20 (18) 14 28

Rocky Mountain/Great Plains 90 78 (70) 52 104

Interior Alaska 100 89 (89) 57 133

All Regions 438 381 (360) 254 590

1 Some territories were excluded from nest success and productivity calculations because they were not checked when nestlings were 

≥28 days old, and thus the outcome was considered unknown.

2 Includes only territories with young ≥28 days old.

3 Maximum number of nestlings ≥28 days old detected on last visit to nest, or count of fledged young if the only nest visit after 27 days 

post-hatch was made after young fledged.
 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

versus natural. Using this information, the estimated 

number of Peregrine Falcon territories in North 

America in 2003 was conservatively estimated at 

3005, including recent data from Canada (400 pairs; 

U. Banasch, pers. commun.), an older estimate from 

Mexico (170 pairs; Enderson et al. 1995), and a rough 

estimate for Interior Alaska (1000 pairs; T. Swem, 

pers. commun.). In the contiguous United States, the 

total number of active territories was estimated to 

be 1435 (Table 3).

Of the 438 territories checked, 350 were on natural 

substrates and 88 were on manmade structures 

(Table 4). Artificial substrates supported 64% of 

eyries in the Midwestern/Northeastern region, 

but only 8% of nests in all other regions combined 

(Figure 3).

Table 2: Territory occupancy, nest success, and productivity for the American Peregrine Falcon, 2003.

Region

% Territory Occupancy1

(90% CI)

% Nest Success2

(90% CI)

Productivity3

(90% CI)

Pacific 83 (78–89) 65 (57–74) 1.45 (1.25-1.66)

Southwestern 78 (67–89) 77 (64–90) 1.73 (1.36-2.10)

Midwestern/Northeastern 91 (86–95) 76 (69–82) 2.09 (1.85-2.32)

Southeastern 95 (93–98) 78 (70–86) 1.56 (1.32-1.79)

Rocky Mountain/Great Plains 87 (81–92) 74 (66–82) 1.49 (1.29-1.68)

Interior Alaska 89 (84–94) 64 (56–72) 1.494 (1.27-1.72)

All Regions 87 (85–89) 71 (67–74) 1.64 (1.53-1.75)

1 Percent of checked territories occupied by a pair.

2 Percent of occupied territories with one or more young ≥28 days old.

3 Average number of young ≥28 days old produced by occupied territories with known outcomes.

4 Average age of young was 14 days on Yukon and 21-28 days on Tanana rivers, thus productivity estimates are unlike in other 

regions. In a previous year on Yukon, a count of nestlings and later of fledglings of a sample of nests yielded a 21% mortality rate 

(Skip Ambrose, pers. comm.). If applied to both rivers, this mortality correction would result in a productivity estimate of 1.18 

(90% CI 0.95-1.41); however, this calculation is also not equivalent to our method of estimating productivity in other regions.

Table 3: 2003 continental population estimate, American Peregrine Falcon.

Region Pairs (new1) Total

Pacific 472 (87)

Rocky Mountain/Great Plains 367 (10)

Southwestern 260 (0) 1099 (97)

Midwestern/Northeastern 315 (24)

Southeastern 21 (2) 336 (26)

Subtotal (lower 48) 1435 (123)

Interior Alaska 1000 (8)

Canada 400

Mexico 170

Total2 3005 (131)

1

Number of new territories reported in 2003 versus 2002; in some cases these updated older data (5 year-old data in one case).

2

Includes conservative estimates for some States (e.g. CA, AK) where exact pair count not known. 
Results 

Figure 2: American Peregrine Falcon, 2003, regional estimates of territory occupancy, nest success, 

productivity, and 90% confidence intervals. Target values (solid lines at 84% territory occupancy and 68% 

nest success), and threshold levels (dashed lines at 71% territory occupancy, 55% nest success, and 1.0 

Productivity). Monitoring Regions are: P, Pacific; SW, Southwestern; M/N, Midwestern/Northeastern; SE, 

Southeastern; RM, Rocky Mountain/Great Plains; AK, Interior Alaska; and combined data for all regions.

78

91 95

87 89 87

83

40

60

80

100

120

% Territory 

Occupancy

65

77 76 78

64

71 74

40

60

80

100

% Nest Success

1.45

1.73

2.09

1.56 1.49 1.49

1.64

0.50

1.00

1.50

2.00

2.50

Monitoring Regions

Young/Occupied Territory

P SW M/N SE RM AK All
 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

Table 4: Numbers of nest sites on natural versus manmade substrates, American Peregrine Falcon, 2003.

Regions Nest Site 

Substrate

Territories 

Checked

Territories Occupied 

(known outcome)

Successful 

Nests Young

Pacific

Manmade 15 14 (14) 8 21

Natural 81 66 (61) 41 88

Southwestern

Manmade 0 0 0 0

Natural 36 28 (26) 20 45

Midwestern/

Northeastern

Manmade 61 58 (57) 45 132

Natural 34 28 (25) 17 39

Southeastern

Manmade 8 7 (7) 7 13

Natural 13 13 (11) 7 15

Rocky Mountain/

Great Plains

Manmade 4 3 (3) 2 3

Natural 86 75 (67) 50 101

Interior Alaska

Manmade 0 0 0 0

Natural 100 89 (89) 57 133

All Regions

Manmade 88 82 (81) 62 169

Natural 350 299 (279) 192 421

Total 438 381 (360) 254 590

Figure 3: Percentage of eyries on natural versus manmade substrates in the Midwestern/Northeastern 

Monitoring Region and all other regions combined, American Peregrine Falcon, 2003.

Midwestern/Northeastern Region

(n = 95)

Manmade

64%

Natural

36%

All Other Regions

(n = 343)

Manmade

8%

Natural

92%


Discussion

The Monitoring Plan describes three conditions 

that might cause concern about Peregrine Falcons 

in a region or regions and lead to additional action 

by the Service. The three conditions are: estimates 

of territory occupancy or nest success at or below 

the thresholds for agency response, that is, 13 

percentage points below the 1999–2002 targets; or 

if the upper bound of the 90% confidence intervals 

around those estimates are below the 1999–2002 

targets; or if estimates of productivity are below 1.0 

young per successful territory. These thresholds 

were based on data thought to represent healthy 

Peregrine Falcon populations (Hickey 1942, Hickey 

and Anderson 1969, Enderson and Craig 1974, 

Ratcliffe 1993, Hunt 1998, Corser et al. 1999, 

Hayes and Buchanan 2002). In 2003, none of these 

conditions was met (Table 2; Figure 2), giving 

us reasonable confidence that Peregrine Falcons 

continued to thrive in 2003.

In the Southwestern region, however, the confidence 

interval for territory occupancy (67% to 89%) is 

particularly wide; it included the threshold for 

agency response (71%) (Figure 2); this was a 

result not considered in the Monitoring Plan. This 

simply means that territory occupancy may be at 

or below the threshold for agency response. The 

wide confidence interval is due in part to the small 

sample (n = 36), 60 fewer, all in Arizona, than 

our goal of 96 territories per region. Unlike most 

other states, Arizona discontinued monitoring 

in 1997 when the number of active territories in 

the State approached 170 (USFWS 1993); this 

number far exceeded the goal in the recovery plan 

of 46 territories for Arizona (USFWS 1984) and 

approached the 183 territory recovery goal for the 

entire Rocky Mountain/Southwestern recovery 

region. Re-establishing the network of volunteers 

and agency contacts necessary to carry out 

monitoring in 2003 and compiling an updated list 

of recently occupied territories was difficult. These 

and other factors contributed to the shortfall of 

territories in the Southwestern Region. In 2004 and 

2005 territories were re-located throughout Arizona. 

Sixty of these will be monitored in 2006, increasing 

our Southwestern sample to 96, and thus achieving 

our monitoring objectives for statistical power in the 

Southwestern region.

Although it is not the intent of the Monitoring Plan 

to track the total numbers of breeding Peregrine 

Falcons in any region, the monitoring effort does 

incidentally reveal new territories. The estimate 

of 3005 pairs in North America is similar to the 

2500–3000 pairs estimated in White et al. (2002). 

Reporting of these data was not universal, however, 

so the regional and North American sums should be 

considered conservative estimates.

Data on nest placement were also additional to 

the main purpose of the monitoring plan. It is not 

surprising that the majority of nesting pairs in 

the Midwestern/Northeastern Region selected 

manmade structures for their eyries; steep, tall 

cliff faces, classical Peregrine Falcon nesting sites, 

are fewer in the Midwest than in Western or some 

Northeastern States. Nonetheless, Peregrine 

Falcons thrive on smokestacks, tall structures in 

cities, and on bridges over rivers in this region, 

where territory occupancy, nest success, and 

productivity are among the highest in the nation 

(Table 2). In 13 Midwestern states, Ontario, and 

Manitoba, productivity from nests on smokestacks 

and buildings was higher than on cliffs or bridges 

(Tordoff et al. 2003).
10 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

Conclusion

The Monitoring Plan was carried out with few 

complications at the national level. The sample 

from the Southwestern region was smaller than 

recommended, however steps were taken in 2004 

and 2005 to prepare for full-scale monitoring in 

2006. With the caveat that the Southwestern region 

was under-sampled, the data collected in 2003 show 

territory occupancy, nest success, and productivity 

of Peregrine Falcons to be at healthy levels in every 

monitoring region, and show numbers of pairs 

continuing to increase across the United States. 

No additional reviews or requests for additional 

research or monitoring occurred as a result of these 

data. Monitoring will be conducted again in 2006 

in accordance with the monitoring plan (USFWS 

2003), and funding has already been received by 

regional coordinators to ensure that States and 

other partners receive timely support in advance of 

the 2006 field season to carry out their monitoring 

activities in accord with the monitoring plan 

(USFWS 2003).
11

Literature Cited

Cade, T. J., J. H. Enderson, and J. Linthicum. 1996. 

Guide to management of Peregrine Falcons at the 

eyrie. The Peregrine Fund, Boise, ID.

Cade, T. J., J. H. Enderson, C. G. Thelander, 

and C. M. White, eds. 1988. Peregrine Falcon 

populations; their management and recovery. The 

Peregrine Fund, Boise, ID.

Corser, J. D., M. Amaral, C. J. Martin, and C.C. 

Rimmer. 1999. Recovery of a cliff-nesting 

Peregrine Falcon, Falco peregrinus, population in 

northern New York and New England, 1984-1996. 

Canadian Field-Naturalist 113:472-480.

Enderson, J. H., and J. Craig. 1974. Status of the 

Peregrine Falcon in the Rocky Mountains in 1973. 

Auk 91:727-736.

Enderson, J. H., W. Heinrich, L. Kiff, and C. M. 

White. 1995. Population changes in North 

American Peregrines. Transactions of the 60th 

North American Wildlife and Natural Resources 

Conference 1995:142-161.

Hayes, G. E., and J. B. Buchanan. 2002. Washington 

State status report for the Peregrine Falcon. 

Washington Department of Fish and Wildlife, 

Olympia, WA.

Hickey, J. J. 1942. Eastern population of the Duck 

Hawk. Auk 59:176-204.

Hickey, J. J., and D. W. Anderson. 1969. The 

Peregrine Falcon: life history and population 

literature, p. 3-42. In J. J. Hickey [ed.], Peregrine 

Falcon populations: their biology and decline. 

University of Wisconsin Press, Madison, WI.

Hunt. W. G. 1998. Raptor floaters at Moffat’s 

equilibrium. Oikos 82:191-197.

Kiff, L. F. 1988. Commentary—Changes in the status 

of the Peregrine in North America: an overview, 

p. 123-139. In T. J. Cade, J. H. Enderson, C. G. 

Thelander, and C. M. White [eds.], Peregrine 

Falcon populations: their management and 

recovery. The Peregrine Fund, Boise, ID.

Pagel, J. E. 1992. Protocol for observing known 

and potential Peregrine Falcon eyries in the 

Pacific Northwest, p. 83-96. In J. E. Pagel [ed.]. 

Proceedings: Symposium on Peregrine Falcons 

in the Pacific Northwest. Administrative Report, 

Rogue River National Forest, Medford, OR.

Ratcliffe, D. 1993. The Peregrine Falcon, Second 

edition. T. & A. D. Poyser, London.

Scheaffer, R. L., W. Mendenhall III, and R. L. Ott. 

1996. Elementary Survey Sampling, 5th ed. 

Duxbury Press, Boston, MA.

Steidl, R. J., J. P. Hayes, and E. Schauber. 1997. 

Statistical power in wildlife research. Journal of 

Wildlife Management 61:270-279.

Tordoff, H. B, J. A. Goggin, and J. S. Castrale. 

2003. Midwest Peregrine Falcon restoration, 

2003 annual report. Museum of Natural History, 

University of Minnesota, Minneapolis, MN.

U.S. Fish and Wildlife Service. 1982a. Pacific Coast 

recovery plan for the American Peregrine Falcon 

(Falco peregrinus anatum). U.S. Fish and 

Wildlife Service, Portland, OR.

U.S. Fish and Wildlife Service. 1982b. Recovery plan 

for the Peregrine Falcon, Alaska population. U.S. 

Fish and Wildlife Service, Anchorage, AK.

U.S. Fish and Wildlife Service. 1984. American 

Peregrine Falcon Rocky Mountain population 

recovery plan. U.S. Fish and Wildlife Service, 

Denver, CO.

U.S. Fish and Wildlife Service. 1991. Peregrine 

Falcon (Falco peregrinus) eastern population 

revised recovery plan. U.S. Fish and Wildlife 

Service, Hadley, MA.

U.S. Fish and Wildlife Service. 1993. American 

Peregrine Falcon (Western States) (Falco 

peregrinus anatum): addendum to the Pacific 

Coast (1982) and Rocky Mountain/Southwest 

(revised, 1984) American Peregrine Falcon 

recovery plans. U.S. Fish and Wildlife Service, 

Portland, OR.
12 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

U.S. Fish and Wildlife Service. 1999. Endangered 

and threatened wildlife and plants; final rule to 

remove the American Peregrine Falcon from 

the Federal list of endangered and threatened 

wildlife, and to remove the similarity of 

appearance provision for free-flying peregrines in 

the conterminous United States. U.S. DOI., U.S. 

Fish and Wildlife Service. Federal Register 64: 

46542-46558.

U.S. Fish and Wildlife Service. 2003. Monitoring 

plan for the American Peregrine Falcon, A species 

recovered under the Endangered Species Act. 

U.S. Fish and Wildlife Service, Divisions of 

Endangered Species and Migratory Birds and 

State Programs, Pacific Region, Portland, OR.

White, C. M., N. J. Clum, T. J. Cade, and W. G. Hunt. 

2002. Peregrine Falcon (Falco peregrinus). In

A. Poole and F. Gill, editors. The birds of North 

America, No. 660. The Academy of Natural 

Sciences, Philadelphia, Pennsylvania; The 

American Ornithologists’ Union, Washington, 

D.C.
13

Appendix A: List of Data Collectors by 

Monitoring Region and State

Pacific Region

California: Paul Andreano, Doug Bell, Dave 

Bogener, John Boyd, Jeb Bridges, Kristi Bridges, 

Roy Burke, Ken Dexter, Gregg Doney, Sandra 

Fleming, Jerry Franklin, Dennis Garrison, 

Larry Goldzband, David Gregoire, Bill Grummer, 

Gary Guliasi, Jim Hallisey, Keith Hamm, Terry 

Hunt, Bob Isenberg, Josh Koepke, Christopher 

Kuntzsch, Brian Latta, Janet Linthicum, Jeff 

Maurer, David Moore, Laura Nelson-Bradley, 

Henry Pontarelli, Richard Rowlette, Andrew 

Santa Cruz, Christy Sherr, Steve Shubert, Jeff 

Sipple, Glenn Stewart, David Suddjian, Nick 

Todd, Brian Walton.

Idaho: Brian Aber, Carl Anderson, Bill Arnold, Mike 

Biggs, Joanne Bonn, Michael Boyles, Rita Dixon, 

Robin Garwood, Bruce Haak, Lauri HanauskaBrown, Kristin Hassalblad, Jim Johnston, 

Jim Juza, Ed Levine, Alvin McCollough, Julie 

Mulholland, Greg Painter, Dave Roberts, Hadley 

Roberts, Rex Sallabanks, Audra Serrian, Dave 

Spicer, Beth Waterbury, Rick Weaver.

Nevada: Pat Cummings, Bob Furtek, Ross Haley, 

Kris Kenney, Christy Klinger, Sara McFarland, 

Julien Peligrini, Vaughan Spearman, Cris 

Tomlinson, Jason Williams,

Oregon: Ken Allison, David Anderson, Ralph 

Anderson, Janet Anthony, Norm Barrett, Jean 

Battle, Matteo Bianchi, Gary Birch, Jeff Bohler, 

Laura Bradley, Cindy Bright, Bonnie Brown, 

Matt Broyles, Charlie Bruce, Tim Burnett, 

Steve Burns, Todd Bush, Francesca Cafferata, 

Doug Calvin, Steve Carter, Gary Clowers, 

Kevin Crowell, Eric Cummings, Dick Davis, 

Ray Davis, Marilyn Elston, Kendel Emmerson, 

Bus Engsberg, Delena Engsberg, Ron Escano, 

Roli Espinosa, Sharnelle Fee, Bev Fenske, Dan 

Fenske, Kim Garvey, Elizabeth Gayner, Lynn 

Gemlo, Damon Goodman, Eric Greenquist, Bob 

Gritsky, Lori Haack, Jim Harper, Jim Heaney, 

Jaime Heinzelmann, Mark Henjum, Will High, 

Kelli Hoffman, Cindy Humphreys, Frank Isaacs, 

Kimberly Judson, Shane Kamrath, Anthony 

Kerwin, Kevin Kocarek, Anson Koehler, Tuch 

Korevia, Rod Krahmer, Katrina Krause, Karen 

Kronner, Kirk Lunstrum, Bill Marshall, Jay 

Martini, Nathan Maxon, Chad McLane, Tom 

Meek, Michael Mefford, Rolando MendezTreneman, Mike Miller, John Moore, Raul 

Morales, Gail Morris, Reed Mortenson, Bill 

Munro, Tom Murtagh, Jane Olson, Charlotte Opp, 

Ralph Opp, Joel Pagel, Rosa Palarino, Amanda 

Pantovich, Dan Patterson, Mark Penninger, 

Lindsey Perrine, Dave Peterson, Summer Phelps, 

Glenn Phillips, Dave Pitkin, Kristal Plotts, Bill 

Price, Jim Quincy, Erich Reeder, Rick Rodriguez, 

Trisha Roninger, Bob Sallinger, Jennifer Sanborn, 

Kevin Sands, Ruby Seitz, Hud Sherlock, Jean 

Sherlock, Ryan Siebdrath, Devin Simmons, 

Melonie Smeltz, Jeff Stephens, Terri Stone, 

Kristin Thompson, Melinda Trask, Sally Villegas, 

Angie Voigt, Eugene Voyton, Daryl Whitmore, 

Grant Wiegert, Holly Witt, Barbara Woodhouse, 

John Woodhouse, Tiff Young.

Washington: Chris Addison, Bud Anderson, David 

Anderson, Jeff Bernatowicz, Russ Canniff, 

Tom Cyra, Bob Davies, Howard Ferguson, Pat 

Fowler, Steve Goodman, Stuart Johnson, Lee 

Kantar, Michael MacDonald, Tom McCall, Ruth 

Milner, Kim Romain-Bondi, Tricia Thompson, 

Dave Volsen.

Southwestern Region

New Mexico: Sandy Williams

Texas: Judy Brinkerhoff, Jessica Erickson, Joselyn 

Fenstermacher, Allison Freeman, Meaghan Hicks, 

Katrina Jensen, Dan Leavitt, Gary Luce, Steve 

McAllister, Colm Moore, Amy Mowat, Marcos 

Paredes, Casey Parks, Melissa Powell, Michael 

Ryan, Joe Sirotnak, Raymond Skiles, Reine 

Winote, David Yim, Mark Yuhas.

Midwestern/Northeastern

Connecticut: Julie Victoria.

Delaware: Holly Niederriter.

Iowa: Theresa Chapel, Pat Schlarbaum

Illinois: Matt Gies, Mary Hennen, Kanae 

Hirabayashi, Dave Sysczak, Friends of the 

Uptown Theatre.

Indiana: Susan Banta, Dwayne Burke, John 

Castrale, Greg Costakis, Tony DiPaolo, Susan 

Laflin, John Meyer, Jeff Neumeier, Ted Weitzel, 

John Winebrenner, Wayne Yoder.

Maine: Charlie Todd.
14 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

Maryland: Craig Koppie.

Massachusetts: Tom French.

Michigan: Tim Payne, Ray Rustem, Judy Yerkey.

Minnesota: Bob Anderson, Jim Fitzpatrick, Brad 

Johnson, Warren Lind, Marco Restani, Wendell 

Snider, Bud Tordoff.

New Hampshire: John Kanter, Chris Martin.

New Jersey: Kathy Clark.

New York: Barbara Loucks, Chris Nadareski.

Ohio: Tom Henry, Rick Jasper, Dave Scott.

Pennsylvania: Dan Brauning.

Virginia: Jeff Cooper, Rick Reynolds, Bryan Watt.

Vermont: Doug Blodgett, Steve Faccio, 

Margaret Fowle.

Wisconsin: Mike Crivello, Greg Septon.

Southeastern

Georgia: Jim Ozier.

Kentucky: Shawchyi Vorisek.

North Carolina: Chris McGrath.

South Carolina: Mary Bunch, Harrison.

Tennessee: Dubke, Stiver, Keith Watson.

Rocky Mountain/Great Plains

Colorado: Jerry Craig, Jim Enderson, Jeff Lucas, 

Terry Meyers, Dinosaur National Monument, 

Mark Roberts, Marni Zaborac.

Montana: Byron Crow, David Lockman, Ralph 

Rogers, Jay Sumner.

Utah: Frank Howe.

Wyoming: Terry McEneaney, Bob Oakleaf, 

Susan Patla.

Interior Alaska

Skip Ambrose, Peter Bente, Bob Ritchie, 

John Wright.

We apologize to anyone we left off the list.
15

Appendix B: Sample Peregrine Falcon 

Monitoring Form

(Used in 2003; updated version at http://www.fws.gov/endangered/recovery/peregrine/.)

Observation Date:(M/D/YR) Nest Site Name or # 

Which Territory Visit is this? (circle one) 1st 2nd 3rd 4th

Nest Site (circle one): Manmade Natural

Observation Time: Begin End 

(Should be at least 4 hrs if occupancy, nest age, or nestling number are in question)

Observer(s) 

Phone:_________________ Email:________________________ Agency/NGO 

WEATHER: Precipitation Wind (speed estimate) 

Temperature Cloud cover (%) 

Note conditions at beginning (beg.) and ending (end) of observation period if different

Observation post: (distance in meters) 

Approx. Nesting Phase (determined how?) 

Peregrines present: (define as ad. male, ad. female, ad. unknown, subad. Male, subad. Female, or subad. 

Unknown, and number of each.) 

Behaviors observed: 

Nest observed? Y N Feeding at nest observed? Y N Eggs observed? Y N Unk

How many eggs? Young observed (AGE)? 

How many young? Other observations: 

Occupied Territory—a territory where either a pair of Peregrines are present (2 adults or adult/subadult 

mixed pair), or there is evidence of reproduction (e.g., one adult is observed sitting low in the nest, eggs or 

young are seen, or food is delivered into eyrie). Occupancy must be established for at least one of two or 

more 4-hour site visits. Nest Success—the percentage of occupied territories in which one or more young 

≥28 days old is observed, with age determined following guidelines in Cade et al. (1996). Productivity—the 

number of young observed (at ≥28 days old) per occupied territory, averaged across the monitoring region.

Paperwork Reduction Act: The total annual public reporting burden for gathering information under this Peregrine Falcon monitoring 

plan is estimated to be 190 hours in 2002, 220 hours in 2003, and 270 hours in 2004. This includes time for reviewing instructions, 

gathering and maintaining data, and preparing and transmitting reports. Comments regarding the burden estimate or any other aspect 

of the reporting requirement(s) should be directed to the Service Information Collection Clearance Officer, MS 222 ARL SQ, Fish and 

Wildlife Service, 1849 C Street NW, Washington, DC 20240.

An agency may not conduct and a person is not required to respond to a collection of information unless a currently valid OMB control 

number is displayed.
16 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

Appendix C: Monitoring Data

Table C-1: Monitoring Data

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

Pacific Monitoring Region

CA-01 nat Y 2/0 Y 2

CA-02 nat Y 2/0 N 0

CA-04 nat Y 2/0 Y 2

CA-10 nat Y 2/0 Y 1

CA-11 nat Y 2/0 Y 4

CA-14 nat Y 2/0 N 0

CA-15 nat Y 2/0 unk unk

CA-21 nat Y 2/0 Y 3

CA-23 nat Y 2/0 unk unk

CA-26 nat Y 2/0 Y 1

CA-27 nat Y 2/0 Y 3

CA-31 mm Y 2/0 Y 1

CA-32 mm Y 2/0 Y 2

CA-46 nat Y 2/0 N 0

CA-48 nat N 0 N 0

CA-54 nat N 0 N 0

CA-56 nat Y 2/0 Y 1

CA-62 nat Y 2/0 N 0

CA-63 nat Y 2/0 Y 2

CA-64 nat Y 2/0 Y 2

CA-66 mm Y 2/0 Y 4

CA-75 mm Y 2/0 N 0

CA-78 mm Y 2/0 N 0

CA-82 mm Y 2/0 Y 2

CA-84 nat Y 2/0 unk unk

CA-85 nat Y 2/0 Y 1

CA-88 nat Y 2/0 Y 2

CA-89 nat Y 2/0 Y 2

CA-90 nat Y 2/0 Y 2

CA-17 nat Y 2/0 unk unk

ID-03 nat Y 2/0 N 0

ID-07 mm Y 2/0 Y 4

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.
Appendix C 17

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

ID-09 nat Y 2/0 Y 3

ID-11 nat Y 2/0 Y 2

ID-12 nat N 0 N 0

ID-16 nat N 0 N 0

ID-17 nat Y 2/0 N 0

ID-20 nat Y 2/0 Y 2

ID-24 nat Y 2/0 Y 1

NV-01 nat Y 2/0 unk unk

NV-04 nat N 1/0 N 0

NV-11 nat Y 2/0 Y 1

OR-01 nat Y 2/0 N 0

OR-05 nat N 1/0 N 0

OR-07 mm Y 2/0 Y 4

OR-10 nat N 0 N 0

OR-13 nat N 1/0 N 0

OR-14 nat Y 2/0 Y 2

OR-15 nat Y 2/0 Y 3

OR-21 nat Y 2/0 N 0

OR-22 mm Y 2/0 Y 1

OR-23 nat Y 2/0 N 0

OR-30 nat Y 2/0 Y 2

OR-31 nat Y 2/0 Y 3

OR-39 nat N 0 N 0

OR-41 mm N 0 N 0

OR-47 nat Y 2/0 Y 3

OR-49 nat Y 2/0 N 0

OR-53 nat Y 2/0 Y 1

OR-56 nat Y 2/0 N 0

OR-57 nat Y 2/0 N 0

OR-62 nat Y 2/0 N 0

OR-63 nat Y 2/0 Y 3

OR-68 nat Y 2/0 Y 4

OR-71 nat N 1/0 N 0

OR-72 mm Y 2/0 Y 3

OR-75 nat Y 2/0 Y 3

OR-77 nat Y 2/0 Y 2

OR-79 nat N 1/0 N 0

OR-84 nat Y 2/0 N 0

OR-86 nat Y 2/0 N 0

OR-90 nat Y 2/0 Y 2

WA-03 nat Y ? Y 2

WA-13 nat Y ? Y 3

WA-15 nat Y 2/0 N 0

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.
18 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

WA-20 nat Y 2/0 Y 2

WA-22 nat Y ? Y 2

WA-24 nat Y 2/0 N 0

WA-25 nat N 0 N 0

WA-29 nat Y 2/0 Y 1

WA-32 nat Y 2/0 Y 4

WA-36 mm Y 2/0 N 0

WA-39 nat N 1/0 N 0

WA-41 nat N 0 N 0

WA-47 mm Y 2/0 N 0

WA-51 nat Y 2/0 N 0

WA-53 nat Y 2/0 Y 1

WA-54 nat Y 2/0 N 0

WA-57 nat Y 2/0 N 0

WA-60 mm Y 1/0 N 0

WA-62 nat Y 2/0 Y 3

WA-63 nat Y ? Y 2

WA-74 mm Y ? N 0

WA-77 nat N 0 N 0

WA-79 nat Y 2/0 Y 2

WA-80 nat Y 2/0 Y 1

Southwestern Monitoring Region

NM-004 nat Y 2/0 Y 1

NM-005 nat Y 2/0 unk unk

NM-007 nat N 1/0 N 0

NM-010 nat Y 2/0 Y 2

NM-011 nat Y 2/0 Y 3

NM-013 nat Y 2/0 Y 2

NM-016 nat Y 2/0 N 0

NM-021 nat N 0 N 0

NM-026 nat Y 2/0 Y 2

NM-029 nat Y 2/0 Y 2

NM-038 nat N 0 N 0

NM-040 nat Y 2/0 Y 1

NM-041 nat Y 2/0 Y 2

NM-042 nat N 0 N 0

NM-046 nat Y 2/0 N 0

NM-050 nat N 0 N 0

NM-055 nat Y 2/0 Y 2

NM-056 nat Y 2/0 Y 3

NM-063 nat Y 2/0 Y 3

NM-066 nat N 1/0 N 0

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.
Appendix C 19

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

NM-069 nat Y 2/0 Y 3

NM-071 nat Y 2/0 Y 3

NM-074 nat Y 2/0 Y 3

NM-075 nat Y 2/0 unk unk

NM-077 nat Y 2/0 N 0

NM-087 nat Y 2/0 Y 4

NM-089 nat Y 2/0 Y 3

NM-090 nat N 1/0 N 0

NM-092 nat Y 2/0 N 0

NM-097 nat Y 2/0 Y 2

NM-099 nat Y 2/0 N 0

NM-100 nat N 1/0 N 0

TX nat Y 2 Y 1

TX nat Y 2 Y 1

TX nat Y 2 N 0

TX nat Y 2 Y 2

Midwestern/Northeastern Monitoring Region

IA-2 mm Y 2 Y 4

IL-7 mm Y 2 Y 3

IN-10 mm Y 2 Y 4

IN-3 mm Y 2 Y 4

IN-6 mm Y 2 Y 4

IN-7 mm Y 2 Y 4

IN-8 mm Y 2 N 0

MI-5 mm Y 2 Y 4

MI-7 mm Y 2 N 0

MN-11 mm Y 2 Y 1

MN-17 mm Y 2 Y 3

MN-19 mm Y 2 N 0

MN-21 mm Y 2 Y 3

MN-27 mm Y 2 N 0

MN-5 nat Y 2 unk unk

MN-9 mm Y 2 N 0

OH-1 mm Y 2 Y 2

OH-11 mm Y 2 Y 1

OH-15 mm Y 2 Y 3

OH-6 mm Y 2 N 0

WI-14 mm Y 2 Y 3

WI-2 mm Y 2 Y 4

WI-9 mm N 1 N 0

NH05 nat Y 2 Y 2

NH06 nat Y 2 Y 2

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.
20 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

NH07 nat Y 2 Y 2

NH11 nat Y 2 N 0

NH14 nat Y 2 Y 2

VT5 nat Y 2 N 0

VT6 nat Y 2 N 0

VT12 nat Y 2 Y 3

VT13 nat N 1 N 0

VT14 nat Y 2 Y 3

VT15 nat Y 2 N 0

VT16 nat Y 2 Y 1

VT17 nat Y 2 Y 3

VT20 nat Y 2 N 0

VT22 nat Y 2 N 0

VT28 nat Y 2 Y 2

DE04 mm Y 2 Y 3

MD01 mm Y 2 Y 4

MD04 mm Y 2 Y 2

MD05 mm Y 2 N 0

MD06 mm Y 2 Y 4

MD07 mm Y 2 Y 3

MD11 mm Y 2 Y 3

CT03 nat N 1 N 0

ME01 nat Y 2 N 0

ME03 nat Y 2 Y 2

ME04 nat Y 2 N 0

ME07 nat Y 2 Y 3

ME16 nat N 0 N 0

NY01 nat Y 2 unk unk

NY05 nat N 0 N 0

NY06 nat Y 2 Y 2

NY08 nat Y 2 unk unk

NY10 nat Y 1 Y 3

NY15 nat N 0 N 0

NY16 nat Y 2 Y 3

NY28 nat Y 2 Y 2

NY30 mm Y 2 Y 4

NY34 mm Y 2 N 0

NY35 mm Y 2 N 0

NY40 mm Y 2 Y 2

NY41 mm Y 2 Y 4

NY42 mm N 0 N 0

NY44 nat Y 2 Y 1

NY46 mm Y 2 Y 3

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.
Appendix C 21

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

NY48 mm Y 2 Y 3

NY51 nat Y 2 Y 3

NY53 nat N 2 N 0

MA01 mm Y 2 Y 3

MA04 mm Y 2 Y 1

MA08 mm Y 2 Y 3

NJ02 mm Y 2 N 0

NJ06 mm Y 2 Y 4

NJ07 mm Y 2 Y 3

NJ09 mm Y 2 Y 1

NJ12 mm Y 2 Y 2

NJ14 mm Y 2 Y 4

NJ19 mm Y 2 Y 3

NJ21 mm Y 2 Y 2

PA11 mm Y 2 Y 2

RI02 mm Y 2 unk unk

VA02 mm Y 2 Y 3

VA05 mm Y 2 Y 5

VA09 mm Y 2 Y 2

VA10 mm Y 2 Y 4

VA14 mm N 0 N 0

VA17 mm Y 2 Y 2

VA18 mm Y 2 N 0

VA22 mm Y 2 Y 0

VA24 mm Y 2 Y 3

VA25 mm Y 2 Y 3

VA26 mm Y 2 N 0

Southeastern Monitoring Region

NC1 nat Y 2/0 N 0

NC2 nat Y 2/0 Y 3

NC3 nat Y 2/0 N 0

NC4 nat Y 2/0 Y 1

NC5 nat Y 2/0 N 0

NC6 nat Y 2/0 N 0

NC7 nat Y 2/0 Y 3

NC8 nat Y 2/0 Y 2

NC9 nat Y 2/0 Y 2

NC10 nat Y 2/0 Y 2

SC1 nat Y 2/0 unk unk

KY1 mm N 1/0 N 0

KY2 mm Y ? Y 4

KY3 mm Y ? Y 2

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.
22 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

KY4 mm Y 2/0 Y 1

KY5 mm Y 2/0 Y 3

TN1 nat Y 2/0 unk unk

TN2 mm Y 1/1 Y 0

TN3 nat Y 2/0 Y 2

GA1 mm Y 2/0 Y 2

GA2 mm Y 1/? Y 1

Rocky Mountain/Great Plains Monitoring Region

CO-02 nat Y 2/0 Y 2

CO-112 nat Y 2/0 Y 1

CO-115 nat N 0 N 0

CO-122 nat Y 2/0 Y 2

CO-123 nat N 1/0 N 0

CO-124 nat Y 2/0 N 0

CO-131 nat N 0 N 0

CO-132 nat Y 2/0 Y 2

CO-138 nat Y 2/0 N 0

CO-147 nat Y 2/0 unk unk

CO-149 nat Y 2/0 Y 3

CO-152 nat N 1/0 N 0

CO-22 nat Y 2/0 N 0

CO-32 nat Y 2/0 Y 2

CO-41 nat Y 2/0 unk unk

CO-42 nat Y 2/0 N 0

CO-43 nat Y 2/0 N 0

CO-54 nat Y 2/0 N 0

CO-58 nat Y 2/0 Y 3

CO-69 nat Y 1/1 N 0

CO-71 nat Y 2/0 N 0

CO-75 nat N 0 N 0

CO-92 nat Y 2/0 N 0

CO-94 nat Y 2/0 N 0

CO-97 nat Y 2/0 N 0

Mt-03 nat Y 2/0 Y 2

Mt-06 mm N 0 N 0

Mt-10 nat N 0 N 0

Mt-11 nat Y 2/0 Y 2

Mt-12 nat Y 2/0 Y 4

Mt-17 nat N 0 N 0

Mt-24 nat Y 2/0 Y 2

Mt-26 nat Y 2/0 Y 3

Mt-27 nat Y 2/0 Y 3

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.
Appendix C 23

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

Mt-29 nat Y 2 Y 3

Mt-33 nat Y 2 Y 3

Mt-34 nat Y 2 Y 1

Mt-35 nat Y 2 Y 2

Mt-41 nat N 0 N 0

Mt-43 nat N 0 N 0

UT-012 mm Y 2 Y 1

UT-016 mm Y 2 N 0

UT-017 mm Y 2 Y 2

UT-024 nat Y 2 Y 1

UT-025 nat Y 1 N 0

UT-027 nat Y 2 Y 2

UT-029 nat Y 2 unk unk

UT-030 nat Y 2 unk unk

UT-033 nat Y 2 N 0

UT-037 nat Y 2 Y 2

UT-040 nat Y 2 Y 1

UT-041 nat Y 2 Y 1

UT-046 nat Y 2 N 0

UT-047 nat Y 2 Y 2

UT-064 nat Y 2 unk unk

UT-072 nat Y 2 unk unk

UT-081 nat Y 2 Y 3

UT-090 nat Y 2 Y 2

UT-098 nat Y 1 Y 2

UT-099 nat Y 2 Y 1

UT-100 nat N 0 N 0

UT-105 nat Y 2 Y 1

UT-118 nat Y 2 Y 2

UT-124 nat Y 2 unk unk

UT-127 nat Y 2 Y 1

UT-129 nat Y 2 Y 2

UT-131 nat Y 2 unk unk

UT-135 nat Y 2 Y 2

UT-136 nat Y 2 Y 2

UT-144 nat Y 2 Y 1

UT-162 nat Y 2 Y 2

UT-163 nat Y 2 Y 1

UT-172 nat N 0 N 0

UT-177 nat Y 2 Y 2

UT-181 nat Y 2 N 0

WY-2 nat Y 2 Y 2

WY-10 nat Y 2 Y 2

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.
24 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

WY-12 nat Y 2 Y 3

WY-14 nat Y 2 Y 2

WY-20 nat Y 2 Y 2

WY-23 nat Y 2 Y 2

WY-24 nat Y 2 N 0

WY-25 nat Y 2 Y 2

WY-27 nat Y 2 Y 2

WY-32 nat Y 2 Y 3

WY-33 nat Y 2 Y 4

WY-42 nat Y 1 N 0

WY-45 nat Y 2 Y 1

WY-60 nat Y 2 Y 1

WY-61 nat Y 2 Y 2

Interior Alaska Monitoring Region

Yukon River km

3 nat Y 2 Y 2

9.5 nat Y 2 N 0

14 nat Y 2 Y 2

20 nat Y 2 Y 2

26 nat Y 2 Y 3

31.5 nat Y 2 Y 2

38 nat Y 2 N 0

45 nat Y 2 N 0

48.5 nat Y 2 Y 3

51.5 nat Y 2 N 0

56 nat Y 2 Y 2

57.5 nat Y 2 N 0

73.5 nat Y 2 N 0

76.5 nat Y 2 Y 4

82.5 nat Y 2 N 0

88 nat Y 2 Y 3

90.5 nat Y 3 Y 3

95.5 nat Y 2 N 0

112 nat Y 2 Y 1

117 nat Y 3 Y 2

123_0 nat Y 2 N 0

124 nat Y 2 Y 2

128 nat Y 3 N 0

138 nat Y 2 Y 3

141.5 nat Y 2 Y 1

149.5 nat Y 2 Y 3

154 nat Y 2 Y 3

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.
Appendix C 25

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

180 nat Y 2 Y 2

184 nat Y 2 N 0

187 nat Y 2 Y 2

191.5 nat Y 2 N 0

195 nat Y 2 Y 2

196.6 nat Y 2 N 0

197 nat Y 2 N 0

199 nat Y 2 Y 3

200.5 nat Y 4 Y 2

205 nat Y 2 N 0

208.5 nat Y 2 N 0

210.5 nat Y 2 N 0

211.5 nat Y 2 N 0

224.5 nat Y 2 Y 3

229 nat Y 2 N 0

233 nat Y 2 Y 2

235 nat Y 2 N 0

239.5 nat Y 2 Y 2

243.2 nat Y 2 N 0

248.5 nat Y 2 Y 2

254 nat Y 2 Y 1

Tanana River km

96.5 nat Y 2 Y 2

103 nat Y 2 Y 1

130 nat Y 2 N 0

135 nat Y 2 Y 4

181 nat Y 2 Y 3

188 nat Y 2 N 0

205 nat Y 2 Y 4

211 nat N 1 N 0

214 nat N 0 N 0

221.5 nat Y 2 Y 4

243 nat Y 2 Y 4

244.5 nat Y 2 Y 2

246 nat N 0 N 0

247 nat N 0 N 0

248 nat Y 2 Y 4

257 nat Y 2 Y 2

258.5 nat Y 2 Y 2

269.5 nat Y 2 N 0

273 nat Y 2 Y 3

280.5 nat Y 2 Y 1

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.
26 Monitoring Results for Breeding American Peregrine Falcons (Falco peregrinus anatum), 2003

FWS ID Nest Substrate1 Occupied?1 Adult/Subadult1 Successful?1 Young1

281.5 nat N 0 N 0

283.5 nat Y 2 Y 2

288.5 nat N 0 N 0

299 nat Y 2 N 0

320 nat Y 2 Y 4

323 nat Y 2 N 0

335 nat N 0 N 0

337.5 nat Y 2 Y 1

371 nat Y 2 Y 4

376 nat Y 2 N 0

380 nat Y 2 Y 1

386 nat Y 2 Y 1

405 nat Y 2 Y 3

408 nat N 0 N 0

411 nat Y 2 Y 2

412 nat Y 2 Y 2

414.5 nat N 1 N 0

427 nat Y 2 Y 1

431 nat Y 2 N 0

436.5 nat Y 2 N 0

438.5 nat Y 2 Y 3

443 nat Y 2 N 0

449 nat Y 2 N 0

459.5 nat Y 2 Y 1

470.5 nat Y 2 Y 2

544.5 nat N 1 N 0

550.5 nat Y 2 Y 3

551.5 nat Y 2 Y 1

578 nat Y 2 Y 2

586 nat Y 2 Y 2

610 nat N 1 N 0

613 nat Y 2 N 0

1–Nest Substrate (s) are nat (natural, e.g. cliffs) or mm (manmade, e.g. bridges and buildings). Occupied and Successful nests either 

Y = Yes or N = No (definitions in Methods). Adult/Subadult often not recorded, thus one number appears. Number of Young listed, or 

unk if last visit was made with young <28 d old.

U.S. Department of the Interior

U.S. Fish & Wildlife Service

Route 1, Box 166

Sheperdstown, WV 25443

http://www.fws.gov

March 2006