bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Support for a New Drift Block Design to Assess Seabird Mortality from Oil Pollution
Authors: Wiese Francis K. , Jones Ian L. , Nettleship D. 
Published: September 2019

Abstract
Seabird mortality from large oil spills and chronic oil pollution is often significant. Total mortality estimates are derived from counts of dead birds that wash ashore and are corrected for numbers lost at sea. Past attempts to estimate proportion of birds that die at sea and wash ashore have included several experiments using carcasses and different types of wooden drift blocks. Results varied greatly depending on environmental conditions and distance from shore where blocks or carcasses were released. Wind seemed to be the predominant factor determining movement over large distances, whereas tidal currents influenced deposition on specific beaches. Determining timing and location of arrival of dead birds on beaches are crucial for accurate mortality estimates. Drift experiments using beached birds that have already drifted at sea for an undetermined length of time are inaccurate due to natural buoyancy loss and decomposition. To determine accuracy of drift block designs used in the past, we compared drift characteristics and patterns between four drift block designs and fresh murre (Uria spp.) carcasses. Our experiments showed that drift blocks used in the past have none of the drift characteristics of dead seabirds, because they have much larger areas exposed to wind and hence drift much faster and farther than murre carcasses. Past mortality estimates using those blocks are therefore doubtful. The drift block design that most accurately mimicked murre carcass drift during our experiments was a 9 × 9 × 14.5 cm wooden block with a 450 gram steel weight that adjusts buoyancy and area exposed to the wind. We propose that in areas where murres are predominant victims of oil spills, that block design be used for all future estimates of oiled seabird mortality.
Fitness-related Consequences of Relaying in an Arctic Seabird: Survival of Offspring to Recruitment Age
Authors: Hipfner J. Mark , Nettleship D. 
Published: September 2019

AbstractSeasonal declines in rates of renesting following clutch loss are common features of avian breeding, and are generally thought to reflect underlying seasonal declines in food availability that lower survival prospects for late-season offspring. However, in Thick-billed Murres (Uria lomvia), long-lived Arctic seabirds that lays a single-egg clutch, previous research has shown that early laying females will continue to relay until late in the laying period. Moreover, hatching success is similar between first and replacement attempts, as are nestling growth and survival, when parental quality is controlled. I compared survival between departure from the breeding site and recruitment age (4–5 years) for Thick-billed Murres that hatched from first and replacement eggs, but that were raised by parents that laid their first eggs early in the season. Replacement-egg offspring hatched and departed the colony about three weeks later than did first-egg offspring, but despite that, they were no less likely to survive to recruitment age. That result indicates that the potential fitness payoff from a replacement egg is similar to that from a first egg for the more capable members of the population. I suggest that an adequate and predictable late-season food supply ultimately underlies the considerable relaying capacity exhibited by Thick-billed Murres.
Protein Requirements of a Specialized Frugivore, Pesquet's Parrot (Psittrichas fulgidus)
Authors: Pryor Gregory S. , Levey Douglas J. , Dierenfeld Ellen S. , Bosque C. 
Published: September 2019

AbstractFor those few bird species that are exclusively frugivorous, the low protein content of fruits is likely a major nutritional constraint. Physiological mechanisms that allow strict frugivory remain enigmatic, but reduced protein requirements may suffice. We investigated protein requirements of Pesquet's Parrot (Psittrichas fulgidus), a highly specialized, obligate frugivore. Three isocaloric, fruit-based diets of varying protein content (6.1, 3.3, and 2.6% dry mass crude protein) were used in feeding trials lasting three to five days per diet. A minimum dietary protein requirement of 3.2% dry mass was estimated from balance trials. Endogenous nitrogen losses were 0.05 gN kg−0.75 day−1 and nitrogen equilibrium occurred at 0.32 gN kg−0.75 day−1. Those values are extremely low compared to those of granivorous and omnivorous bird species, but higher than those of nectarivorous species. In terms of nitrogen losses and requirements, Pesquet's Parrot most closely parallels the highly frugivorous Cedar Waxwing (Bombycilla cedrorum). Thus, reduced protein requirements appear to play an important physiological role in ability of highly frugivorous birds to subsist on fruit diets.
Bounce and Double Trill Songs of Male and Female Western Screech-Owls: Characterization and Usefulness for Classification of Sex
Authors: Herting Brian L. , Belthoff James R. , Kroodsma D. 
Published: September 2019

AbstractBoth sexes of adult Western Screech-Owls (Otus kennicottii) sing in response to playback of conspecific song within their territories. Two primary songs are the bounce and double trill. Using sonographic analysis of tape-recorded vocalizations, our study quantified characteristics of bounce and double trill songs uttered by individuals within a population of Western Screech-Owls inhabiting riparian woodlands in southwestern Idaho. We asked if songs of males and females differed and, if so, how accurately could songs be classified by sex. On average, male bounce songs were ∼30% lower in frequency than bounce songs of females, but song duration, note duration, number of notes per bout, and internote duration did not differ. Similarly, double trill songs of males were significantly lower in frequency than those of females, and double trill songs uttered by females had significantly greater internote distances in the leading portion. A discriminant model based on frequency at maximum amplitude of bounce songs correctly classified all males and females in our sample. Presence of sex-specific patterns of vocalizations in that species would allow owls to assess the sex of potential intruders and respond appropriately. Moreover, sonographic analysis of Western Screech-Owl songs provides a means for noninvasive classification of sex.
Is Diet-shifting Facilitated by Modulation of Pancreatic Enzymes? Test of an Adaptational Hypothesis in Yellow-rumped Warblers
Authors: Ciminari M. Eugenia , Afik Daniel , Karasov William H. , Caviedes-Vidal Enrique , Blem C. 
Published: September 2019

AbstractMany birds exhibit seasonal switches in diet and thus alter nutrients predominating their food intake. We tested for dietary modulation of pancreatic enzymes in Yellow-rumped Warblers (Dendroica coronata), a species for which such dietary changes are documented. Birds were fed three diets formulated from either fruit, insect, or seed. We predicted that pancreatic carbohydrase amylase, and the proteases trypsin and chymotrypsin, would be modulated in direct correlation with relative levels of dietary carbohydrate and protein, respectively. In contrast to the prediction, there was no significant dietary effect on activities of amylase and chymotrypsin, and a significant change in trypsin activity (highest on seed diet) occurred in the wrong direction with regard to the prediction. Considering the statistical power of our tests, we conclude that Yellow-rumped Warblers represent a case of only modest ability, at best, to modulate pancreatic enzymes. For some diets, especially high-starch diets that they digest relatively poorly and on which they tend to lose body mass, they may lack sufficient enzyme and hence are constrained in their dietary niche.
True Winter Range of the Veery (Catharus Fuscescens): Lessons for Determining Winter Ranges of Species That Winter in The Tropics
Authors: Remsen Jr. J. V. , Moore F. 
Published: September 2019

AbstractMost recent references describe the winter range of the Veery (Catharus fuscescens) as including an extensive area from northern Colombia, Venezuela, and Guyana south to south-central Brazil. Analysis of seasonal distribution of specimen records in South America, however, shows that 91 of 105 specimens were taken during spring and fall, not winter; the remaining 14, taken from 2 December to 20 February, are all from three small areas at the periphery or south of the Amazon basin. Thus, the true winter range is almost completely south and east of the area generally described. The seasonal distribution of specimen records is consistent with observational data from South America and banding data from the Neotropics. Although those data must be treated cautiously, it appears that the true winter range of the Veery is in south-central and southeastern Brazil, an area where habitat destruction threatens many natural habitats, rather than in the relatively undisturbed areas of western Amazonia. Widespread erroneous portrayal of the winter range of the Veery seems to have been caused largely by the assumption that the species winters in South America wherever it has been recorded and by overlooking a previously published analysis of its winter distribution.
Phylogeny and Systematics of Ground Rollers (Brachypteraciidae) of Madagascar
Authors: Kirchman Jeremy J. , Hackett Shannon J. , Goodman Steven M. , Bates John M. , Prum R. 
Published: September 2019

AbstractWe studied relationships of five extant members of the endemic Malagasy family Brachypteraciidae, the ground rollers, using several mitochondrial genes (cytochrome-b, NADH dehydrogenase 2, 12S ribosomal RNA, and cytochrome oxidase I). As outgroups, we used other coraciiforms including the Cuckoo Roller (Family Leptosomatidae, Leptosomus discolor), several true rollers (Corcaciidae) and a tody (Todidae). Partial sequences of the Long-tailed Ground Roller (Uratelornis chimaera) were obtained from toe pad samples taken off museum specimens. For a combined data set of all genes, Kimura two-parameter distances between sequences of the five ground roller species were high, averaging 11% divergence. For several species, samples were available from widely separated geographic regions and intraspecific sequence divergence was low (≤0.8%). Unweighted and weighted parsimony and maximum-likelihood analyses consistently recovered monophyly of the family, a sister relationship between Brachypteraciidae and Coraciidae, and monophyly of one of three currently recognized ground roller genera (Atelornis). At the base of the Brachypteraciidae clade, we could not fully resolve relationships between Uratelornis and two species currently placed in Brachypteracias. Because of the uncertainty of basal nodes in our phylogenetic reconstructions, we recommend returning B. squamigera to the monotypic genus Geobiastes. High levels of divergence among ground rollers are similar to levels found in other avian groups endemic to Madagascar. However, we suggest that molecular divergences appear far too low to be consistent with mid-Eocene fossils attributed to the family.
A Molecular Phylogeny of the Dove Genera Streptopelia and Columba
Authors: Johnson Kevin P. , de Kort Selvino , Dinwoodey Karen , Mateman A. C. , ten Cate Carel , Lessells C. M. , Clayton Dale H. , Sheldon F. 
Published: September 2019

Abstract
Evolutionary history of the dove genus Streptopelia has not been examined with rigorous phylogenetic methods. We present a study of phylogenetic relationships of Streptopelia based on over 3,600 base pairs of nuclear and mitochondrial gene sequences. To test for monophyly of Streptopelia, we used several other columbiform taxa, including Columba (Old and New World), Macropygia, Reinwardtoena, and the enigmatic Pink Pigeon (Nesoenas mayeri). On the basis of our analyses, Streptopelia (as currently defined) is not monophyletic; Nesoenas mayeri is the sister species to S. picturata, resulting in paraphyly of Streptopelia. Three main clades of Streptopelia are identified: (1) S. chinensis plus S. senegalensis, (2) S. picturata plus Nesoenas mayeri, and (3) all other species of Streptopelia. It is unclear whether those clades form a monophyletic group to the exclusion of Old World Columba, but several analyses produce that result. Species of Old World Columba are closely related to Streptopelia, with species of New World Columba clustering outside that group. Taxonomic changes suggested by our results include merging Nesoenas with Streptopelia and changing the generic name for New World Columba species to Patagioenas. Vocal similarities between S. picturata and N. mayeri are striking, given the general diversity of vocalizations in other species.
Site Fidelity, Philopatry, and Survival of Promiscuous Saltmarsh Sharp-Tailed Sparrows in Rhode Island
Authors: DiQuinzio Deborah A. , Paton Peter W. C. , Eddleman William R. , Brawn J. 
Published: September 2019

AbstractWe investigated site fidelity and apparent survival in a promiscuous population of Saltmarsh Sharp-tailed Sparrows (Ammodramus caudacutus) in southern Rhode Island. Based on capture–recapture histories of 446 color-banded sparrows studied from 1993 to 1998 at our primary study site, Galilee, we observed significant variation in apparent survival rates among years, but not between sexes. Return rates of adult males (37.6%) and females (35.6%) were not significantly different during any year. Juveniles exhibited high return rates, ranging from 0 to 44%, with males (61% of returns) more likely to return than females (35%). In addition, we monitored movements of 404 color-banded sparrows at nine satellite marshes in 1997 and 1998, which supported our findings at Galilee and documented intermarsh movements by 10% of all banded birds. Lack of gender-bias in adult dispersal and strong natal philopatry of sparrows in Rhode Island occurs regularly among passerines possessing a variety of mating systems. Despite emancipation from parental and resource defense duties, adult male Saltmarsh Sharp-tailed Sparrows exhibited apparent survival rates similar to adult females. Availability of high-quality breeding habitat, which is patchy and saturated, may be the most important factor limiting dispersal for Saltmarsh Sharp-tailed Sparrows in Rhode Island.
Energetics of Toucans, A Barbet, and A Hornbill: Implications for Avian Frugivory
Authors: McNab Brian K. , Bosque C. 
Published: September 2019

Abstract
Rate of oxygen consumption was measured in eight species of toucans, one barbet, and one hornbill to examine factors that influence their energy expenditures. Basal rate of metabolism in those species, supplemented with measurements from three woodpeckers and three mousebirds, is correlated with body mass and either food habits or climate: temperate acorn- and insect-eating species have basal rates that are ∼70% greater than tropical fruit-eating species. The temperate, insect- or acorn-eating species are woodpeckers, so level of basal rate is also correlated with familial affiliation. The toucans, barbet, and hornbill have basal rates similar to those of frugivorous pigeons and bats, which collectively are low by avian standards. The effects of climate, food habits, and family affiliation on basal rates in endotherms are difficult to separate, given the restricted data set available. Earlier conclusions that the basal rates of birds greatly exceed those of mammals are confounded by character interactions that influence dependence of basal rate on body mass. The largest toucan showed a remarkable ability to reduce energy expenditure at low ambient temperatures without reducing core body temperature, possibly as a result of peripheral vasoconstriction.
Does Kleptoparasitism by Glaucous-Winged Gulls Limit the Reproductive Success of Tufted Puffins?
Authors: St. Clair Colleen Cassady , St. Clair Robert C. , Williams Tony D. , Danchin E. 
Published: September 2019

AbstractInterspecific kleptoparasitism (food stealing) occurs in many seabird species and can sometimes significantly affect host individuals and populations. We investigated effects of kleptoparasitism by Glaucous-winged Gulls (Larus glaucescens) on a population of Tufted Puffins (Fratercula cirrhata) in which almost all chicks die before fledging in some years. Rates of kleptoparasitism were estimated during two seasons and compared with several spatial and temporal factors that have been predicted to influence kleptoparasitism rates both within and among seasons. Kleptoparasitism rates increased from 2% in the first year to 19% in the second, whereas puffin fledging success declined precipitously from 81% in the first year to 11% in the second. Within years, kleptoparasitism rates increased with number of puffins returning with fish, decreased during fair weather, and were unaffected by tidal height. Spatially, those rates increased with puffin burrow density and declined with angle of the nesting slope. Gull kleptoparasitism success increased during foul weather and at higher puffin nesting elevations. Despite those associations, survival of puffin chicks was not influenced by kleptoparasitism activity near their nests although it increased with a combination of low elevation and high slope at the nesting burrow. Neither kleptoparasitism nor predation by gulls were exceptional relative to other seabird colonies and they were unlikely to cause reproductive failures that characterize puffins at that site. Other factors, particularly food shortages at sea, merit further attention in explaining those failures.
Prefledging Energy Requirements in Shorebirds: Energetic Implications of Self-Feeding Precocial Development
Authors: Schekkerman Hans , Visser G. Henk , Blem C. 
Published: September 2019

AbstractUnderstanding ecological consequences of avian developmental modes requires knowledge of energy requirements of chicks of different positions in the precocial–altricial spectrum, but those have rarely been measured in birds with self-feeding precocial young. We studied prefledging energy budgets in chicks of Black-tailed Godwit (Limosa limosa) and Northern Lapwing (Vanellus vanellus) in the field and in the laboratory. Lapwings show slower growth than godwits, reaching a 29% lower fledging mass (142 vs. 201 g) in a 32% longer period (33 vs. 25 days). Daily energy expenditure (DEE), measured by the doubly labelled water (DLW) technique, and daily metabolized energy (DEE plus energy deposited into tissue) increased proportionally to body mass at similar levels in both species. Total metabolized energy (TME) over the fledging period was 8,331 kJ in godwits and 6,982 kJ in lapwings, 39 and 29% higher than an allometric prediction (Weathers 1992). That suggests that self-feeding precocial chicks have high energy requirements compared with parent-fed species, due to costs of activity and thermoregulation associated with foraging. Those components made up 50–53% of TME in the shorebirds, more than twice as much as in seven parent-fed species for which DLW-based energy budgets are available. In captive lapwings and godwits growing up under favorable thermal conditions with food readily accessible, thermoregulation and activity costs were 53–58% lower and TME was 26–31% lower than in free-living chicks. The proportion of TME allocated to tissue formation (13–15% deposited as tissue plus 10–12% synthesis costs) was low in the shorebirds, and reductions in food intake may therefore sooner lead to stagnation of growth than in parent-fed chicks. Furthermore, the need to forage limits potential for saving energy by reducing activity in periods of food scarcity, because that will further decrease food intake. Self-feeding precocial chicks thus seem to operate within fairly narrow energetic margins. At the same time, self-feeding may allow birds to use food types that could not be profitably harvested if they had to be transported to the young.
Geographical Variation in the Contact Calls of Orange-Fronted Parakeets
Authors: Bradbury Jack W. , Cortopassi Kathryn A. , Clemmons Janine R. , Kroodsma D. 
Published: September 2019

Abstract
We examined patterns of geographic variation in contact calls of Orange-fronted Parakeets (Aratinga canicularis) during the nonbreeding season. Calls were recorded throughout the range of that species in Costa Rica. Recordings of wild-caught birds held for one to two weeks indicated that each individual favors one dominant call type and different birds use different favored calls. We used that fact to cull replicate calls from the same individual in field recordings of flocks observed at various locations throughout the sample area. Remaining recordings from a given year were submitted to spectrographic cross-correlation and principal coordinates analysis as described by Cortopassi and Bradbury (2000). Principal coordinates were then correlated with site location using MANOVA. Call durations were also examined for geographical patterns. Like sympatric Yellow-naped Parrots (Amazona auropalliata) studied over the same region by Wright (1996), Orange-fronted Parakeets exhibited significant geographic variation but, unlike the larger species, showed no discrete dialect patterns. Call duration varied clinally but with different patterns for the Nicoya Peninsula and the Guanacaste mainland. Two principal coordinates also showed clinal variation even after removing any correlated duration effects. Scale over which local calls were statistically homogeneous was 7–10 km. We compared that figure to home ranges of 18 birds radio-tracked concurrently with call sampling. Both range areas and range lengths were asymptotic after a week of tracking. Asymptotic range lengths were 2–9 km. Scale of movements of birds, at least during that period, was thus similar to distance within which calls tended to be statistically homogeneous. This study and that by Wright show that several well-known patterns of geographical variation seen with passerine song are replicated quite closely in contact calls of parrots, despite the fact that the functions of vocal signals are quite different in the two taxa.
How Many Baskets? Clutch Sizes That Maximize Annual Fecundity of Multiple-Brooded Birds
Authors: Farnsworth George L. , Simons Theodore R. , Brawn J. 
Published: September 2019

Abstract
We developed deterministic models on the basis of nest survival rates and renesting behavior capable of predicting annual fecundity in birds. The models calculate probabilities of fledging from one to four nests within a discrete breeding season. We used those models to address theoretical issues related to clutch size. In general, birds require at least one day to lay an egg, and many species delay incubation until their entire clutch is laid. Because it takes longer to complete a larger clutch, and fewer such clutches can fit into a limited breeding season, there exists a clutch size for which annual fecundity is maximized. We asked, for a given amount of reproductive effort (i.e. a set number of eggs), does the age-old maxim “don't put all your eggs in one basket” apply? If so, in how many “baskets” should a nesting bird place its eggs? The answer depends on both likelihood of nest predation and length of the breeding season. Those results are consistent with the observed increase in clutch size with latitude (shorter breeding season length) and larger clutch sizes characteristic of cavity-nesting species (with higher nest survival rates). The models also predict that the size of replacement clutches should decrease as the breeding season progresses, and that intraseasonal decline in clutch size should be more pronounced when the breeding season is short.