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In most Neotropical Psittacidae the existence and extension of long-distance movements are poorly understood. The Blue-and-yellow Macaw (BYM; Ara ararauna) has a wide range in South America and its occurrence seems to be seasonal or sporadic in some areas. This study describes the results of BYM data collected in a monthly regular field effort from July 2001 to June 2005 at the RPPN SESC Pantanal reserve (Mato Grosso state, Brazil). The aim of the study was to evaluate the BYM's use of the reserve resources, its displacements and possible causes. Every observed BYM flock or individual had its date, hour, geographic coordinates, flock size, and activity (landed, feeding, or displacement) registered. The flight azimuth of continuous and straight displacements was also registered. We used circular statistics and vector pairs (azimuth and flock size) to analyze the observed intraday, monthly, and yearly displacements pattern. A total of 189 flocks and 854 BYM were recorded, the average size being 4.5 ± 3.7 individuals per flock. The prevalent activity category was displacement (85.2 ± 3.8%) and the flocks occurred with non-uniform distribution through the year. Seventy one percent of all flocks were registered in only 4 months, each one with a statistically significant well-defined flight bearing direction pattern. The mean vector angles calculated for the January/February data (279°/288°) were the opposite of those obtained for the May/June data (98°/110°). The intraday data showed no change in the main flight direction pattern when morning and afternoon data were compared, indicating they were not night roosting/feeding areas movements. The same months through the 4 analyzed annual cycles had the majority of the records. This directional and repetitive pattern does not fit in circadian or nomadic displacements, but suggests seasonal movements of the BYM in the studied area. The observed directions, period, and seasonal direction change of flight paths are consistent with pre- and post-reproductive periods observed in the central region of Brazil. However, still unknown is their origin and destination, as well as the involved mechanisms.
Migration strategies in the avian world are often compared at the species level and evaluated relative to general ecology and constraints such as molting and breeding timetables. The advancement of tracking technology provides an opportunity to explore variation in more specific migration tactics within species and their populations as it relates to demographic and environmental factors throughout the annual cycle. We compare migration timing among 4 populations of Bobolink (Dolichonyx oryzivorus) from across the breeding range using data from light-level geolocators. The date of departure from the breeding grounds and the duration of southbound migration differed among breeding populations, and were more variable for eastern breeding populations compared to western populations farther from the main migration corridor. Despite variation in both timing and distance from the corridor among breeding populations, date of arrival at the major southbound stop in the Llanos of South America remained synchronous, but less so than previously described. Weekly flight distances were highly variable and did not differ among populations. Duration of northbound migration did not differ among populations and was half as long as the southbound migration. Our findings show Bobolink populations breeding near the species' relatively narrow migration corridor in the southeastern United States were more variable in terms of how they reached the first lengthy stop in the Llanos, suggesting more flexibility in migration tactics. Breeding locations were not associated, however, with the timing or duration of the remainder of their migratory schedule. Our findings support the hypothesis that food resources, both historical and present, drive and also modify the endogenous migration schedule of this flocking species with a split migration.
Efficient targeting of limited conservation resources requires a consistent understanding of the distribution and habitat needs of populations of concern. Both Louisiana and Texas Seaside Sparrows (Ammospiza maritima fisheri and A. m. sennetti, respectively) occur along the Texas coast, but confusion remains about the geographic distribution and status of Texas Seaside Sparrows. Given there has been relatively little attention focused on Seaside Sparrows in Texas since Griscom's “Notes on Texas Seaside Sparrows” (1948), we provide here an update to (1) clarify the status of Seaside Sparrows as year-round, breeding residents south to the Rio Grande; (2) highlight important differences in the habitats used by Seaside Sparrows across the Texas coast; and (3) expand on previous population genetic analyses by incorporating additional samples. The current understanding of the population biology of Seaside Sparrows in southern Texas is insufficient for developing sound conservation strategies: the southernmost populations of Texas Seaside Sparrows are small, isolated, and occupy a unique habitat with a limited distribution. Additional information regarding the distribution, population size, and demographic trends of these populations is needed.
The Atlantic Forest in eastern South America harbors 849 bird species, of which 216 are endemic and 122 threatened with extinction. It is also one of the 25 biodiversity hotspots recognized throughout the world. Within this biome, the Serra do Mar stands out as an important area of endemism in South America. Nonetheless, ornithological knowledge of the Serra do Mar remains underestimated and incomplete. One lacunae of information for the Serra is a region called Curucutu, which is adjacent to the largest urban area in South America. The avifauna of Curucutu has been sampled occasionally since 1900, but all of the available data have yet to be published. Therefore, we compiled ornithological data published on Serra do Mar over the last 118 years and undertook a 16-year-long field inventory using 3 methods of data collection simultaneously (visual observations, point counts, and mist nets) for a total of 395 field days. Sampling was performed in forest and natural grasslands along an elevational gradient from 5 to 850 m.a.s.l. A total of 422 species of birds, 128 of which are endemic to the Atlantic Forest and 29 that are threatened with extinction, were documented, thereby illustrating the importance of this region. Of this total, 382 species occur in Núcleo Curucutu do Parque Estadual da Serra do Mar, demonstrating the importance of this reserve to the regional avifauna. We made several significant additions to the avifauna of the region, with only one species, the Black-necked Aracari (Pteroglossus aracari), being considered regionally extinct because of a lack of records since 1900—thus representing a kind of poorly studied extinction that has yet to be investigated and may be happening with much greater frequency in large forested areas of Serra do Mar. Even though the region is partially protected, being a state reserve, its proximity to the largest urban area in South America automatically puts the area under threat, especially considering the disorganized urban growth that has been encroaching upon natural areas of the region. The expansion of current reserves, and the establishment of new protected areas in this region of Serra do Mar is essential for guaranteeing the integrity of this very rich and threatened bird community of the Atlantic Forest.
In temperate regions, winter is characterized by high thermoregulatory demands and low food availability. For woodpeckers, winter survival depends on selecting habitat that provides both suitable roost trees and adequate food. The Red-headed Woodpecker (Melanerpes erythrocephalus) has experienced precipitous declines across much of its range in the past 50 yr, yet causes of declines remain elusive. Although previous studies have focused primarily on the breeding season, understanding winter roost-site requirements is crucial for the maintenance of Red-headed Woodpecker populations across the full annual cycle. Our study investigated winter roost-site characteristics at 3 spatial scales (roost patch, tree, and cavity) in a 41 ha fire-affected forest stand located in northern Virginia. From February to April of 2016 we tracked Red-headed Woodpeckers to 42 roost-sites during evening surveys. To determine the features driving roost-site selection, we compared vegetation surrounding the roost to random sites within the same forest stand, and occupied roost snags (standing dead trees) were compared to the closest available snag. Cavity height and orientation were also examined. We modelled roost-site selection at both the patch and tree scales using logistic regression and identified important variables and their influence by estimating regression coefficients and their model-averaged parameter weights. Habitat within the patch surrounding roost trees had higher basal area of snags and mast-producing trees compared to random sites. Red-headed Woodpeckers selected roost snags with signs of decay and showed preferences based on snag taxon. Our findings indicate that managing land that produces and retains both snags and mature mast-producing trees will benefit overwintering populations of Red-headed Woodpeckers. This study provides the first detailed analysis of winter roost-site selection in this declining species.
Molothrine cowbirds are obligate brood parasites that lay eggs within 5–10 s in the minutes before sunrise. Robust analysis of their position at laying has therefore only been made possible with the development of high-resolution and low-light video recording technologies. From video recordings, we observed the moment of oviposition clearly in 8 and 31 instances of egg laying by Brown-headed (Molothrus ater) and Shiny (M. bonariensis) cowbirds, respectively. Both species laid from an elevated position such that their eggs dropped into nests from an estimated height of 4–8 cm. We propose this elevated laying position has selected for high eggshell strength in cowbirds, because stronger eggshells would be less likely to be damaged during egg laying. Stronger eggshells might also damage other eggs when dropped into the nest, thereby further reducing nestling competition from nest mates and drive selection for cowbird eggshell strength. A role for laying position in the evolution of cowbird egg strength is not mutually exclusive of the view that thickly shelled eggs have evolved as a defense to egg rejection by hosts and/or egg puncture behavior of cowbirds.
Umbrella species management offers a potential solution to the financial and logistical challenges of managing for the many declining species in early-successional forests, a habitat that is also critical for many mature and young forest songbird species during the post-fledging and post-breeding period. We investigated the movements of adult Eastern Towhees (Pipilo erythrophthalmus) during the post-fledging period in 4 km2 landscapes managed for American Woodcock (Scolopax minor), a popular umbrella species candidate for young forest management. Home range size (mean = 2.8 ha, SE 0.33) did not differ during the post-fledging period between adult towhees inhabiting landscapes designated as high-likelihood (HL) or low-likelihood (LL) of woodcock use. Adults moved distances of ∼37–47 m per day during the first 3 weeks of the post-fledging period and this did not differ between the 2 landscapes. In contrast, once their young became independent, adults moved longer distances in HL compared to LL landscapes (49.5 m [SE 2.9] and 36.7 m [SE 3.6], respectively) and these distances increased with home range size and patch size. Landscape features within 100 m of the towhee home range best explained variation in towhee movement distance. Young forest habitat was also the predominant forest type used by adult towhees caring for fledglings throughout the post-fledging period. These results suggest that early successional forest management for woodcock can provide effective breeding habitat for towhees, but likely at a smaller spatial scale than typically managed for woodcock.
We evaluated flight feather molt of Common Grackles (Quiscalus quiscula) collected in North Dakota to determine differences by age and sex and to infer seasonal relationships with nesting and migration. On average, the HY preformative molt started and ended later than the AHY prebasic molt. Percentages of molting AHY males and females in weekly collections were ≥90% beginning the first and fourth weeks of July, respectively. Percentages of molting HY males and females reached ≥90% the first week of August. Both age classes remained >90% in molt through mid-September; thereafter percentages fell rapidly, likely caused by the passing of enough time from average onsets of molts for both resident and northern nonresident populations. By the first week of October, molting HY males and females comprised about 55% of weekly HY collections compared to 9% and 21% for AHY males and females, respectively. Extensive access to commercial sunflower fields perhaps allowed resident and nonresident AHY birds to remain in the area until molt was at or near completion.
Tapaculo (Scytalopus) nests are difficult to find because they are well-hidden in cavities, hence, there is limited information available for this genus. We provide additional data for the nest and eggs and the first descriptions of the nestlings, their growth, and parental behavior of the Blackish Tapaculo (Scytalopus latrans) based on one nest found in western Colombia. The nest was an underground dome composed of moss and rootlets in the side of a slope covered with montane scrub. It contained 2 eggs, both of which hatched 13 days later; the nestlings fledged 13 days after hatching. Nest attentiveness was 76.1% with an average of 18.7 (SD 3.1) trips per day. The parents conducted longer, but more variable, on-bouts of 66.3 min (SD 158.1) compared to shorter off-bouts of 9.3 min (SD 8.7). Combined nestling growth rates averaged 8.7% (SD 4.9) for tarsus, 14.2% (SD 8.3) for wing, and 14.3% (SD 14.36) for weight (% daily growth). Twenty-six days after fledging, a color-banded nestling was caught in a mist net with an assumed parent nearby, approximately 150 m from the nest. Our S. latrans nest, eggs, and clutch size match previous Scytalopus tapaculo nesting reports, but we documented lower nest attentiveness and higher nestling growth rates than previously reported in the genus. Additionally, we observed a parent provisioning nestlings with a frog, which constitutes a significant expansion of the known diet for the family.
The genus Metallura has 9 species in South America distributed mostly at high elevation along the length of the Andes from Bolivia to Venezuela. Six species are known from Peru, 3 of which are endemic, among them M. phoebe, which is distributed between 1,500 and 4,500 m.a.s.l., and inhabits montane scrublands, stands of Puyas (Puya raimondii and P. rauhii), and forests of Polylepis. The present report describes 2 nests found with eggs at 3,670 m.a.s.l. in a high Andean forest of Polylepis rugulosa in the department of Arequipa in southern Peru on 25 March 2016 (Nest 1) and 22 August 2016 (Nest 2). The nests were cup-shaped, constructed of moss and feathers, and placed 1.8–3.5 m above the ground in Polylepis trees. Both nests were built into the underside of larger disused nests, most likely belonging to a species of Asthenes. This report provides an unusual observation of use of another bird's old nest, and differs from previous descriptions of nest placement of this species. Measurements of nests and eggs were taken for the lower nest.
We describe the remigial and rectricial molt sequences of a Ryukyu Scops-Owl (Otus elegans) held in captivity on Minami-daito Island, Nansei Islands, southern Japan. The owl completely shed its remiges and rectrices during its preformative molt as well as during its definitive prebasic molts in 3 consecutive years. In the preformative molt, the primaries were all shed during October, November, and December, in distal order from P1. Although all 4 groups of secondaries were shed in proximal order, the sequence may have been caused by adventitious shedding under captive conditions. During definitive prebasic molt, the primaries were shed in distal order during the period from June to September. The secondaries were shed from 3 nodes in 4 feather groups; 3 groups were shed in proximal order, but the remaining group was shed in distal order. The primary coverts were shed in exact sequence with their corresponding primaries during the definitive prebasic molt, but in a different sequence during the preformative molt. Whereas the greater coverts were shed irregularly during the early part of the primary covert molt, the median coverts were shed during the first half of the primary covert molt. The alula feathers were shed distally over a period of weeks. The right rectrices were shed in irregular order over a short period (12 days) and the left rectrices were shed over a long period (at least 82 days). The shedding sequence of the captive Ryukyu Scops-Owl basically followed the known pattern previously observed in Strigidae species. The captive individual underwent a complete molt when it was a juvenile as a result of being provided with sufficient food, and presumably because of the lower energy demands of being in a cage.
I report human-caused mortality of Andean Condors (Vultur gryphus) in Peru and number of individuals used in Yawar Fiesta celebrations from data collected between 2000 and 2017. From 2014 to 2017, 8 (7 adults and 1 juvenile) Andean Condors were killed and 5 were permanently injured due to poisoning and shooting in central and south Peru. Another 4 individuals were released after being rehabilitated. In all, 40 different individuals (14 males, 20 females, and 6 not determined) were used for Yawar Fiesta celebrations; 96% of these celebrations were held in the Apurimac department in southern Peru. One individual died and 3 were seriously injured after being trampled by bulls during celebrations. Direct and indirect poisoning was the highest cause of mortality in this country. However, given that Yawar Fiesta celebrations are not monitored by government officials and/or researchers, mortality of Andean Condors is higher than reported here. Yawar Fiesta celebrations might have altered the Andean Condor's population structure in the southern Peruvian Andes. In order to guarantee Andean Condor conservation in Peru, local and national government authorities should regulate and forbid the use of Andean Condors in Yawar Fiesta celebrations, while population size and structure of Andean Condors in Apurimac should be assessed.
Although hybrids between captive Accipiter species are known, and hybrids between wild Accipiter species in North America have long been suspected, none have been confirmed to date. However, in 2014, a hatching year Accipiter captured at Cape May, New Jersey, during fall migration, appeared intermediate in size and plumage between a Northern Goshawk (Accipiter gentilis) and a Cooper's Hawk (A. cooperii), and was suspected to be a hybrid. We used data from mitochondrial and nuclear genes to confirm that the hawk was a hybrid female resulting from a cross between a male Cooper's Hawk and female Northern Goshawk.
White-tailed Kites (Elanus leucurus) are grassland raptors that typically breed along coastal regions, particularly in California, southeastern Texas, and southern Florida. This species is irregular in the Texas panhandle, with few confirmed breeding and sighting records. We describe the first breeding record in Lubbock County, Texas, in which a pair of adults successfully raised 2 young in 2017 and may have returned and nested in 2018. Evaluation of cast pellets suggested dietary composition primarily consisted of diurnal rodents. Additionally, we compiled published and unpublished sighting and breeding records for the region and discovered reports for 2 nearby counties (Crosby and Kent counties, Texas) where White-tailed Kites have nested over multiple years, as well as several more counties with sighting records. Our data indicate that the southern extent of the Texas panhandle is now part of the species' breeding or “rare” range.
Plumage coloration is important to birds for communication, camouflage, physiological processes, and mate selection. In rare individuals the coloration is disrupted, which provides opportunities to scrutinize the processes that normally produce it. Male House Finches (Haemorhous mexicanus) normally sport a red head and chest, a brown back, and whitish underparts with light brown streaks. We captured a House Finch with disruptions in both melanin and carotenoid pigmentation in an urban park in Guadalajara, a city in west-central Mexico. The bird was largely orange with little eumelanin pigmentation. This is the first record of which we are aware of a hypomelanistic House Finch with carotenoids that are abnormally distributed and with an overexpression of carotenoid pigments or pheomelanins or both.
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