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A review of all available specimens and the discovery of many unpublished life history notes allows a much more complete picture of the morphology and behavior of the extinct Wake Island Rail (Gallirallus wakensis). The breeding season of the species may have been environmentally influenced but, under favorable conditions, there may have been two broods per year. Small groups of birds engaged in cooperative nesting and prolonged parental care and feeding of the young, probably in part to defend the eggs and young from hermit crabs (Coenobita) and rats (Rattus). The smallest species of its genus, the Wake Island Rail was able to co-exist with Pacific rats (Rattus exulans). Extinction of the rail occurred between 1942 and 1945 as a result of direct predation by thousands of starving Japanese troops and habitat destruction resulting from military alterations and aerial bombardment.
We studied the Black-fronted Piping Guan (Pipile jacutinga), a medium-sized cracid (1.5 kg), endemic of Atlantic rainforest and considered endangered. We present density estimates of Black-fronted Piping Guans derived from line-transect surveys (total effort = 2,246 km) across 11 protected areas (6 continuous mainland areas, 3 non-connected mainland areas, and 2 inshore islands) in São Paulo State, southeastern Brazil. Both islands and the continuous mainland forests of Paranapiacaba massif had the highest density estimates of the species. The largest continuous mainland Atlantic Forest (Serra do Mar massif) had the lowest density estimates and the species was absent in some regions of this mountain range. All non-connected mainland forests also had low density estimates or absence of the species. Our data indicate the Black-fronted Piping Guan is not extremely sensitive to habitat disturbance and the major threat to its conservation is most likely from illegal hunting. The absence or low density estimates of the species in three survey sites is of special concern, because it is known guans are important in seed dispersal, which may have long-term consequences for forest regeneration.
We examined the effects of habitat change on Cerulean Warbler (Dendroica cerulea) populations at stops along Breeding Bird Survey (BBS) routes in the central Appalachians. We used aerial photographs to compare early (1967/1971), middle (1982/1985), and late (2000/2003) periods and compared 1992 and 2001 National Land Cover Data (NLCD). Mean Cerulean Warbler detections per stop decreased at 68 BBS stops between the early (0.05) and middle (0.01) time periods and their distribution became more restricted (15 vs. 3% of stops), but the amount of deciduous/mixed forest increased. Mean detections at 240 stops decreased from the middle (0.09) to the late (0.06) time periods, but the deciduous/mixed forest land cover and fragmentation metrics did not change. The amounts of deciduous/mixed forest, core forest area, and edge density in the NLCD analysis decreased from 1992 to 2001, whereas the amount of non-forest land cover increased. The number of Cerulean Warbler detections did not change (1992 = 0.08, 2001 = 0.10; P = 0.11). The lack of concordance between Cerulean Warbler detections and broad habitat features suggests that smaller, microhabitat features may be most important in affecting Cerulean Warbler breeding habitat suitability.
We evaluated seabird attendance and incidental mortality at coastal trawl vessels targeting Argentine red shrimp (Pleoticus muelleri) in the Isla Escondida fishing area, Argentina, during 2006–2007 and 2007–2008. Eight seabird species attended vessels, and the most frequent and abundant seabird (percent occurrence, mean number per haul) in the two seasons was the Kelp Gull (Larus dominicanus) (100%, 112.3 and 100%, 263.4, respectively), followed by the Black-browed Albatross (Thalassarche melanophris) (85%, 17.6, and 90%, 32.4, respectively). Eleven Magellanic Penguins (Spheniscus magellanicus) and one Imperial Shag (Leucocarbo atriceps) were killed in nets with a mean capture rate of 0.003 and 0.0003 birds per haul, respectively. The estimated total number of birds killed was 53 penguins and five shags considering the total number of hauls made by the fishery in the two seasons. No contacts between seabirds and warp cables were recorded. Coastal shrimp vessels generally operated between 15 and 20 km offshore, at a mean distance from the main Kelp Gull colony (Punta Tombo) of 43.9 km. At least 100 fish and invertebrate species were discarded, mostly Argentine hake (Merluccius hubbsi). Total amount discarded per season by this coastal fishery in the two seasons was estimated at 3,284 and 6,590 tonnes, respectively. The coastal shrimp fishery in the Isla Escondida area appears to have a small impact on seabirds in terms of incidental mortality but provides significant amounts of supplementary food during the breeding season of the Kelp Gull.
Rapid classification of a study subject's gender is critical for many ecological, behavioral, and conservation projects. We evaluated sexual-size dimorphism of adult Westland Petrels (Procellaria westlandica), a large nocturnal colony-nesting seabird, using linear discriminant function analysis and compared our results to birds classified using standard DNA gender identification techniques. The results revealed a strong pattern of sexual dimorphism (Wilks' Lambda = 0.43, F7,29 = 5.6, P < 0.001) in the standard discriminant function analysis despite an unbalanced sex ratio in our sample of adults captured at the breeding colony. Minimum bill depth and head length, of the seven morphometric characters we measured, successfully assigned the correct gender to 95% of all individuals sampled (n = 37). We provide a canonical classification function of morphological traits that may be used in the field to rapidly differentiate adult females and males of this rare petrel species.
The Hyacinth Visorbearer (Augastes scutatus) is a poorly known hummingbird endemic to the Cadeia do Espinhaço in southeastern Brazil and is classified as near threatened with global extinction. We verified size dimorphism of males and females, describe the plumage patterns of juveniles, and detail the reproductive period of this species in Serra do Cipó National Park within the municipality of Morro do Pilar in the State of Minas Gerais, Brazil during August 2007 to July 2009. Adult males were significantly larger than adult females in all measurements assessed. Variables that best differentiate males and females are body mass, total body length, occipital width, bill length, and wing chord. We demonstrated that it may be possible to assign gender of the majority of young of this species, based primarily on the color of the side of the neck and the tract of feathers that circles the visor. There is some indication of a greater concentration of reproductive effort during the dry season, when more juveniles and active nests were recorded. However, we captured fledged young in January, February, and March supporting a breeding period throughout the year for the Hyacinth Visorbearer. This suggests rainfall in the region is the most influential factor in timing of breeding of this species.
We studied the population relationships of Krüper's Nuthatch (Sitta krueperi) by capturing 82 individuals using mist nets in six different areas in Turkey during the breeding season, from March to June 2005–2008. Forty-one different morphometric characters were measured. Morphometric characters measured (x ¯ ± SD) were: body mass = 13.11 ± 0.88 g, wing length = 74.79 ± 2.35 mm, bill length = 17.65 ± 0.76 mm, and tarsus length = 19.10 ± 0.93 mm, respectively. A stepwise discriminant analysis of four populations retained seven statistically significant measurements: body mass, wing length, length of P 8, alula, bill height, back nail, and left nail. These analyses allowed discrimination among populations. The population in the Aladağlar Mountains differed from others even though it overlapped with the population in the Lütfi Büyük Yıldırım Research Forest, and marginally with the population at Kartalkaya Mountain. Cross validation for the other three populations confirmed large overlap in morphometric characteristics although the population at the Lütfi Büyük Yıldırım Research Forest seemed to be intermediate between populations at Aladağlar Mountains and in the Kazdağları Mountain-Kartalkaya Mountain complex.
Hyrcanian forests in the northern Alborz Mountains contain many resident and migrant passerines, but the ecological relationships of the species are obscure. We identified the ecological factors (forest structure, type, and topography) that could explain the distribution of the Eurasian Nuthatch (Sitta europaea) and its' habitat suitability in this region. Significant habitat parameters for presence-absence of Eurasian Nuthatch were height, diameter, stand, and type of trees. Our model successfully predicted the presence probability of nuthatches and that suitable habitats strongly depend on abundance of old trees, especially Oriental beach (Fagus orientalis) and European hornbeam (Carpinus betulus). These data suggest forest structure is the key factor in bird habitat use and suitability, and reveal the necessity of adaptive logging activities in Hyrcanian forests.
We studied the breeding ecology of the Emei Shan Liocichla (Liocichla omeiensis) in two nature reserves (Laojunshan and Wawushan) in Sichuan, China from March to August 2009 and April to August 2010. The breeding density (mean ± SE) was between 1.20 ± 0.46 and 1.55 ± 0.56 males/km2, and the breeding season was from late April to mid-August and from mid-May to late August in Laojunshan Nature Reserve in 2009 and 2010, respectively. This species used the edges of or gaps within natural broadleaf forest between elevations of 1,450 and 2,150 m for nesting. Vegetation around nests was mainly bamboo (Chimonobambusa szechuanensis), small shrubs, and lianes with few large trees. Nests were cup-shaped with a mean height of 137.5 ± 4.6 cm above the ground. Nests were mainly in C. szechuanensis. Females laid one egg per day in the morning and the mean (± SE) clutch size was 2.9 ± 0.2 eggs. Incubation started after the last egg was laid. Both males and females were observed participating in incubation, provisioning, and brooding the nestlings. Hatching success, fledging success, and nest success were 58.6, 70.8, and 27.5%, respectively. Nest predation and human disturbances were the two main factors affecting breeding success of Emei Shan Liocichlas.
We studied Marsh Grassbirds (Locustella pryeri sinensis) and reedbed management from 2006 to 2009 in the Yalu River Estuary Wetlands National Nature Reserve, China. Common reed (Phragmites australis) management was monitored and habitat data for 11 variables from 53 nests were collected over a 4-year period. Calamagrostis epigejos was replaced by aquatic vegetation, none of the nests existed in 2008, and 10 of 11 habitat variables differed between before deep irrigation (>30 cm depth) (2006 and 2007) and after (2009) due to deep water. Mean ± SD clutch size was 4.5 ± 0.83, the daily survival rate was 92.3%, and overall nest success was 12.5%. Cover of total grasses accounted for 17.7% of the changes in nest height. Reed cutting and irrigation influenced the local breeding population of Marsh Grassbirds. Sound management practices could benefit Marsh Grassbirds and other grassland passerines.
We used mist netting in the Chamela-Cuixmala Biosphere Reserve to assess the population phenology of the Flammulated Flycatcher (Deltarhynchus flammulatus), a poorly-known dry forest endemic of the Mexican Pacific Slope. We captured 135 birds (first records only) during 23,515 net hrs over a period of several years which suggests this flycatcher is common at the reserve. Monthly averages of captures (including monthly recaptures) differed between seasons with a peak (71%) during May to August (end of dry season to middle of wet season) and fewer (29%) captures during the rest of the year. Flammulated Flycatchers in breeding condition (n = 38) were captured in June and July. Hatching year birds (n = 8) were captured from 10 July through 11 December. We found an active nest in a cavity on 29 June 2010. We observed pieces of snake skin lining the nest, which may indicate a closer relationship with Myiarchus. Additional knowledge on the ecology and breeding biology of the Flammulated Flycatcher is urgently needed for development of effective conservation plans.
Black Phoebes (Sayornis nigricans) persistently pump their tails vertically while perched but the functional causes are unknown. I address four hypotheses about the function of this behavior in this species: (1) tail pumping aids in balance, (2) tail pumping enhances foraging, (3) tail pumping is a signal to territorial intruders, and (4) tail pumping is a signal to potential predators. The balance (mean ± SE; unstable substrates: 0.23 ± 0.024 pumps/sec, stable substrates: 0.22 ± 0.019 pumps/sec), foraging (non-foraging individuals: 0.28 ± 0.036 pumps/sec, foraging individuals: 0.20 ± 0.026 pumps/sec) and intruder (pre-playback trial: 0.20 ± 0.025 pumps/sec, House Finch [Carpodacus mexicanus] control trial: 0.26 ± 0.029 pumps/sec, Black Phoebe experimental trial: 0.17 ± 0.036 pumps/sec) hypotheses did not significantly explain tail pumping behavior. Tail pumping rates increased during predator sound playback (pre-playback trial: 0.23 ± 0.009 pumps/sec, House Finch trial: 0.26 ± 0.016 pumps/sec, Cooper's Hawk [Accipiter cooperii] trial: 0.61 ± 0.013 pumps/sec, post-playback trial: 0.35 ± 0.013 pumps/sec) and were accompanied by a high amount of both approaches (3.8 ± 0.8) and calls (6.7 ± 1.63). These results indicate that S. nigricans may be using tail pumping behavior as a pursuit-deterrent signal to advertise awareness to potential predators.
Hatching asynchrony in altricial songbirds can influence the morphology and behavior of nestling birds. We compared the position of nestling Eastern Bluebirds (Sialia sialis) in the hatching hierarchy to their (1) position in the egg-laying order, (2) rate of nestling begging, (3) circulating corticosterone, (4) size, and (5) plumage coloration. Most nestlings hatched within 36 hrs of each other, and nestlings hatched in the order in which eggs were laid. Early-hatched nestlings were heavier than late-hatched nestlings for the duration of the growth period and begged less intensely than their late-hatched siblings. There was little evidence of severe effects of hatch order. Hatch order did not influence nestling corticosterone levels nor did we find effects of hatch order on ornamental plumage coloration. Our data suggest no long-term effect of hatching asynchrony on the development of sexually selected plumage coloration.
We tracked the development of innate immunity in nestling Tree Swallows (Tachycineta bicolor) and compared it to that of adults using blood drawn from nestlings during days 6, 12, and 18 of the ∼20-day nestling period and from adults. Innate immunity was characterized using an in vitro assay of the ability of whole blood to kill Escherichia coli. The ability of whole blood to kill E. coli increased as nestlings matured. Neither this component of innate immunity nor right wing chord length on day18 were as developed as in adults indicating that development of the innate immune system and growth both continued after fledging. Narrow sense heritability analyses suggest that females with strong immune responses produced nestlings with strong immune responses. These data suggest nestling Tree Swallows allocated sufficient energy to support rapid growth to enable fledging by day 18, but that further development of innate immunity occurred post-fledging.
We investigated associations between Northern Mockingbirds (Mimus polyglottos) and the nest parasite Philornis porteri (Diptera: Muscidae), and how they vary with urbanization in northcentral Florida. Our goal was to ascertain if the ‘parasite-release’ hypothesis could contribute to high reproductive success of Northern Mockingbirds in urban areas. We collected 26 nests in 2007 and 73 in 2008 that had produced fledglings along an urbanization gradient, and measured the number of nests parasitized and the number of P. porteri in the nests. Habitats differed in prevalence of Philornis parasitism, but not directly in relation to urbanization. Parking lots and wildlife preserves had low levels of parasitism, whereas residential neighborhoods and pastures had significantly higher parasitism prevalence. Parasite prevalence was also significantly and positively affected by nest height and percentage of ground covered by buildings, trees, and open areas in the study site. Our findings do not offer strong support for the ‘parasite-release’ hypothesis in relation to urbanization, but suggest that vulnerability to parasites is habitat-specific.
Avian bamboo specialists are an ecologically distinctive group of birds in the Neotropics with some seedeater species having nomadic movements following bamboo (Guadua, Chusquea or Rhipidocladum) mast seeding. We reviewed the range and seasonal distribution of Blackish-blue Seedeaters (Amaurospiza moesta) using published and unpublished records, museum specimens, sound libraries, and intensive field work. We report the first occurrence of Blackish-blue Seedeaters in the Brazilian State of Mato Grosso, a male collected in Fazenda Baía de Pedra, Cáceres (16° 27′ 29″ S, 58° 09′ 59″ W). We also recorded this species in two localities in the Cerrado region (a tropical savannah) of Minas Gerais: the Santo Antonio River, Presidente Olegário (18° 07′ 48″ S, 46° 11′ 57″ W), and the Abaeté River, São Gonçalo do Abaeté (18° 05′ S, 45° 22′ W). These records represent a remarkable range extension, demonstrating this species is distributed across the Cerrado. We found no evidence of regular large scale or local movements of this species, which seems to be resident, at least in Argentina, which had the largest data set.
Post-breeding ecology of shrubland passerines prior to onset of migration is unknown relative to dynamics of breeding areas. We radiomarked and monitored 38 Sage Sparrows (Amphispiza belli ssp. nevadensis) at one site in Oregon and two in Nevada from September to mid-November 2007 to track local movements, estimate seasonal range sizes, and characterize weather patterns triggering onset of migration. Median area used by Sage Sparrows monitored between 3 and 18 days during or prior to migration was 14 ha; maximum daily movement was 15 km. Radio-marked Sage Sparrows at each location departed individually, rather than en masse, corresponding with passage of cold front weather systems. Conventional telemetry techniques limited our ability to monitor Sage Sparrows beyond pre-migratory periods and precluded detecting and tracking actual movements during migration.
We report the first detailed account of the breeding biology of the Pectoral Sparrow (Arremon taciturnus). We found 15 dome nests, each containing two eggs in a spherical interior chamber. Eggs were variable in color, ranging from immaculate glossy white to white heavily spotted with brown. Incubation patterns were obtained for six nests for time spans that ranged from 1 to 15 days for a total of 28 days across nests. Incubation in all nests was solely by the female, spending an average of 57% (range = 20–65%) of daylight incubating, leaving the nest an average of 7.4 times per day (range = 4–7) with an average trip length of 46.4 min (range = 6–263 min.). Nest temperature averaged 29.2 ± 2.64° C when the female was incubating and decreased to 26.6 ± 2.43° C during incubation recess. Eggs in only two nests hatched and were monitored for 2 and 9 days. The male provided the young with 75% of the food. Nestlings gained an average of 2.53 g per day. Incubation, provisioning behavior, and egg coloration were similar to other species of Arremon; however, nest shape, location, and materials differ among species.
We report breeding success of Wilson's Plovers (Charadrius wilsonia) on St. Martin in the Lesser Antilles during 2004. We located 35 nests among six wetlands and apparent nest success was 37.1%. Nest initiation on St. Martin was earlier than in the United States and breeding success was higher earlier in the season than later in the season. There were two distinct peaks in nest initiation; the second peak coincided with peak fledging of chicks from the first nest initiation. Nests on St. Martin were associated with bare ground and were much closer together than in previous studies reported elsewhere. Ten nests were predated by feral dogs (Canis lupus familiaris) and three nests were crushed by vehicles.
We describe the nest and egg of the Black-headed Berryeater (Carpornis melanocephala), an Atlantic Forest endemic considered vulnerable to extinction. The nest was in a montane evergreen primary forest area in a tree fork 4.2 m above the ground. It was cup shaped and constructed mainly of leaves and stems, resembling a pile of aerial leaf litter. It held just one egg that was incubated solely by the female. The male was near the nest, and inspected it once while being observed.
We studied nest defense behavior of Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) and Yellow Warblers (Dendroica petechia) in response to two species of common nest destroyers. We presented freeze-dried models of Marsh Wrens (Cistothorus palustris) at Yellow-headed Blackbird nests and House Wrens (Troglodytes aedon) at Yellow Warbler nests during the incubation stage. We presented a Clay-colored Sparrow (Spizella pallida) as a control for both species. Male Yellow-headed Blackbirds responded more intensively to the Marsh Wren model than the control and female blackbirds responded intensively to both models but were more aggressive toward the Marsh Wren. Most Yellow Warblers did not respond to the House Wren model with their typical predator responses (e.g., alarm calls). Some female warblers were aggressive toward the wren model, whereas others sat in their nest. Sitting in the nest as a defense to deter nest destruction by House Wren needs further investigation. Differences in response levels between blackbirds and warblers may be related to differences in levels of nest destruction experienced by the two species or differences in nest defense behaviors used by the two species.
We describe a weather-durable cavity design used successfully by cavity-nesting species native to the eastern USA and, although accessible, avoided by European Starlings (Sturnus vulgaris). The artificial nest cavity was constructed using 9.5-cm inside diameter polyvinyl chloride tubes cut to 27.5-cm lengths. The tubes were mounted horizontally with 5.1-cm entry holes drilled through one of the capped ends. Eastern Bluebirds (Sialia sialis), House Wrens (Troglodytes aedon), and Tree Swallows (Tachycineta bicolor) nested in 49 of 100, newly mounted tubes on utility poles in north-central Ohio, USA from April through June 2009. These species nested in 85% of the tubes during the same period in 2010 and fledged young from 94.1% of nests. We added 10 nest tubes (27.5-cm long × 17-cm inside diam) at sites similar to the smaller tubes in 2010. Two of the larger tubes were used by nesting starlings and six by native species. Cavity vertical depth has been shown to be an important feature in starling nest site selection, but our data from the larger tubes indicate that other factors are likely important. The smaller design could offer nesting opportunities for a range of native cavity-nesting species while limiting use by starlings.
We used micro-computed tomography to examine if medullary bone was present in Wood Thrush (Hylocichla mustelina) and Veery (Catharus fuscescens), two species of Passeriformes. We scanned bones from males and females collected during spring and fall migration, and the breeding season. Medullary bone was found in the humerus, radius-ulna, and tibiotarsus-fibula of a breeding female Wood Thrush and a breeding female Veery, both of which were ovulatory at necropsy. Two other breeding female Wood Thrush, both post-ovulatory at necropsy, did not have medullary bone. We did not observe medullary bone in females collected during spring or fall migration, nor in any males. Our findings support the presence of medullary bone in breeding female passerines, but future studies with larger, targeted sample sizes are needed to examine the phenology of medullary bone formation and resorption, and to explore the extent of medullary bone's role in eggshell formation in passerines.
We tested individual distinctiveness, a prerequisite for individual recognition, in the songs of the suboscine Eastern Wood-Pewee (Contopus virens). Male Eastern Wood-Pewees produce two main song types: ‘pee-ah-wee’ and ‘wee-ooo’ songs. All song variables for both song types, including temporal and frequency variables, showed greater between than within individual variation. Thus, both song types contained the potential to code information on individual identity and quality. Pee-ah-wee songs were more variable than wee-ooo songs, and pee-ah-wee frequency variable measures were the most variable. We correctly assigned 97.5% of pee-ah-wee songs and 95.0% of wee-ooo songs to the bird of origin–demonstrating individual distinctiveness in both main song types.
We analyzed the mitochondrial cytochrome b gene of three vagrant Cave Swallow (Petrochelidon fulva) specimens from Illinois, New York, and New Jersey and compared them to published sequences from across the breeding range of the species. All three specimens were assigned to the southwestern United States/Mexico subspecies (P. f. pallida group) on the basis of plumage coloration. Molecular results reveal that all three birds possess unique and novel mitochondrial haplotypes that are closely related to haplotypes from known P. f. pallida individuals. None of the three haplotypes from the vagrant individuals is within the monophyletic clade of haplotypes that corresponds to the Caribbean subspecies (P. f. fulva).
I observed an Eastern Screech-Owl (Megascops asio) wading to catch fish in a small lake in the Everglades, Florida, USA. This fishing technique has not been recorded previously in this species or in other small owls.