We focus on bird use of clearcuts resulting from even-aged management as part of the Missouri Ozark Forest Ecosystem Project (MOFEP). The long-term nature of MOFEP allows us to present a 15-year monitoring of bird use of MOFEP clearcuts in July using constant effort mist-netting. This provides insight into the dynamics of forest bird use of clearcuts during the post-fledging period for both early succession and mature forest breeding birds. We operated nets ∼10,080 hrs and captured 4,711 individuals, with 2,718 individuals considered mature forest breeding birds, and 1,993 individuals considered early succession species. There were few birds occupying clearcuts in year 1, immediately after cutting. Mean captures of all species as a group showed a significant curvilinear trend over time with an early peak in year 3 to 4 followed by decline. Mean captures of early succession species showed a significant trend of an early peak in year 3 followed by steady decline. Mature forest breeding species captures showed a significant curvilinear trend that increased gradually up to a peak around 6–9 years after harvest and then declined. Capture rates suggest that large numbers of birds use clearcuts in the decade after the clearcuts are formed. The abundance of forest-breeding birds in clearcuts in late summer equals or even exceeds the abundance of clearcut-breeding birds found there. This suggests that clearcuts may be an important habitat for mature forest breeding birds after they breed in mature habitats. More work on post-fledging behavior of migratory birds is needed to determine those species which require early succession habitats such as clearcuts and those species which simply take advantage of such habitats should they occur in the vicinity.

Results of a comprehensive molecular phylogeny of the family Thamnophilidae were consistent with earlier findings that almost all obligate army-ant-followers of the family form a monophyletic group that contains five well-supported clades and encompasses six currently recognized genera: Phaenostictus, Pithys, Willisornis, Gymnopithys, Rhegmatorhina, and Phlegopsis. A comparative analysis of seven suites of morphological, behavioral, and ecological traits within the context of the phylogeny reinforced the validity of five of these genera, but results for the sixth, Gymnopithys, were internally inconsistent and required the description of a new genus, Oneillornis.

We examined the phylogeography of the Western Hemispheric Sedge Wren (Cistothorus platensis) which occurs in grasslands from Canada to Tierra del Fuego. Genetic data indicate that Sedge Wren is paraphyletic with Mérida (Cistothorus meridae) and Apolinar's (Cistothorus apolinari) wrens and the currently recognized Sedge Wren is composed of a minimum of eight species. Speciation within this complex appears to have accelerated with the formation of the Isthmus of Panama which enabled the ancestor to occupy and differentiate in grassland habitats from sea level to above tree line in the Andes on the South American continent. As a result of the dramatic, negative anthropogenic impact on grasslands across the entire Western Hemisphere all species have suffered substantial declines and several are now threatened.

Regional, intratropical avian migrations have rarely been studied. Here, we employ an occurrence records review and ecological niche modeling tools to test the hypothesis that an understudied Neotropical bird, the Little Wood-Rail (Aramides mangle, Rallidae), seasonally migrates between the humid Atlantic coast and the dry Caatinga biome of interior northeastern Brazil. We divided records geographically between coastal and inland, and temporally between wet/breeding and dry/non-breeding seasons. Coastal records peak when inland records are fewest and vice-versa, and independence between season and region in which records were made was statistically rejected. However, ecological niche modeling shows that coastal regions are suitable habitats for A. mangle year-round, and models built with records from each season were considered statistically equivalent. It seems that this species neither performs erratic, unpredictable movements nor typical avian “to-and-fro” migration. Instead, it undergoes periodical expansion of its range and ecological niche to include the Caatinga, where it breeds, in addition to the coast. It might be counterintuitive that a species can occupy two seemingly so disparate habitats, but rails in general are known to be very adaptable and have wide ecological niches. Further study is needed in order to understand the exact nature of this species' movements and the life-cycle of individual birds. But given that most studies of avian movements have focused on temperate species, it is likely that common models of avian migratory behavior will not easily apply to A. mangle nor to other Neotropical species.

We studied the effects on structure of bird assemblages after replacement of native natural habitats by small-scale tree plantations used for recreational purposes. The richness and diversity were similar among habitats; however, the total bird abundance was greater in the tree plantations compared to the natural habitats. Also, we found that small-bodied birds that forage in the foliage had higher abundance in the natural habitats, while larger-bodied species that live in open spaces and forage on the ground occurred in higher abundance in the tree plantations. The comparative evaluation of the seasonal effect on avian assemblages of the contrasting habitats showed that natural habitats had a greater annual fluctuation of abundance values, while the tree plantations were more constant. Our study demonstrates that small-scale tree plantations for recreational purposes exert strong effects on bird assemblages, because they increase the abundance of the generalist and common bird species in the region.

Understanding the breeding ecology of grassland birds is vital for understanding the mechanisms underlying their widespread population declines. We describe the breeding biology of Sprague's Pipit (Anthus spragueii), Vesper Sparrow (Pooecetes gramineus), Savannah Sparrow (Passerculus sandwichensis), Baird's Sparrow (Ammodramus bairdii), and Western Meadowlark (Sturnella neglecta) and quantify the effects of nest predation, brood parasitism, and weather on the nest survival of these species in southeastern Alberta. Nest predation was the primary cause of nest failure, accounting for 75% of all nest losses. Daily survival rates were higher during incubation than the nestling stage for the three sparrow species, and nest survival of Baird's Sparrows was highest at intermediate temperatures. For all five species, clutch size, hatching success, and fledging success were within the range of values previously reported for these species in other parts of their range. Brown-headed Cowbirds parasitized nests of all species except Sprague's Pipit, with 4–11% of nests containing cowbird eggs. Savannah Sparrow experienced the highest frequency of brood parasitism and was the only species to successfully fledge cowbird young. Parasitized nests of Savannah Sparrows had reduced clutch size and hatching success, and fledged fewer young compared to non-parasitized nests. The overall cost of parasitism to Savannah Sparrows was at least 1.7 young per successful nest.

Populations of Red-headed Woodpeckers (Melanerpes erythrocephalus) have declined throughout much of their range. Conservation management to arrest declines or increase populations is difficult, because many aspects of the species' demography remain poorly understood. To address this knowledge gap, we monitored Red-headed Woodpeckers' nests on Fort Drum Military Installation, in northern New York and modeled daily nest survival rate as a function of temporal and habitat-specific covariates. Red-headed Woodpeckers had low overall nest survival rates (nest survival  =  32%), and predation was the leading cause (82%) of nest failure. Cavity concealment had the greatest influence on daily nest survival rate, whereby nests with greater vegetative structure surrounding (within 1 m² of) the nest cavity had higher survival rates, likely because of reduced nest predation. Our estimates of Red-headed Woodpeckers' nest survival were lower relative to other portions of their range and suggest that, at local scales, low reproductive rates near the periphery of the species' distribution may limit population growth.

Plumage coloration within species is often a signal of competitive ability and can influence territorial aggression between males. Agonistic interactions among males of different co-occurring species could result from misidentification (misdirected conspecific aggression). Reflectance spectrometry of plumage coupled with models of avian vision can be used to infer whether plumage color differences can be distinguished by birds. Here we investigate crown coloration similarity as a potential explanation for aggression between the imperiled Golden-winged Warbler (Vermivora chrysoptera) and the comparatively abundant Chestnut-sided Warbler (Setophaga pensylvanica). Because the yellow crown coloration of the two species appears identical to humans, we hypothesized that misidentification of heterospecifics as conspecifics could escalate agonistic interactions. Using museum study skins, we tested whether the yellow crown coloration of the two species should be distinguishable to the birds. Spectral reflectance data demonstrate that plumage color differs between the two species and avian vision models suggest these color differences should be easily discriminated. Thus, we conclude that plumage coloration similarity between these wood warblers is unlikely to cause misidentification of heterospecifics as conspecifics and may just be a result of phylogenic constraint. As populations of Golden-winged Warblers are experiencing accelerating declines, research focusing on the role interspecific competition plays on reduced productivity and survival is warranted.

The Spotted Barbtail (Furnariidae) is poorly studied but shows some extreme traits for a tropical passerine. We located and monitored 155 nests to study this species for 7 years in an Andean cloud forest in Venezuela. Spotted Barbtails have an unusually long incubation period of 27.2 ± 0.16 days, as a result of very long (3–6 hr) off-bouts even though both adults incubate. The long off-bouts yield low incubation temperatures for embryos and are associated with proportionally large eggs (21% of adult mass). They also have a long nestling period of 21.67 ± 0.33 days, and a typical tropical brood size of two. The slow growth rate of the typical broods of two is even slower in broods artificially reduced to one young. Nonetheless, the young stay in the nest long enough to achieve wing lengths that approach adult size.

Seeds and flowers of the leguminous māmane (Sophora chrysophylla) tree are the primary food resource of the federally endangered Palila (Loxioides bailleui; Fringillidae: Drepanidinae), which is now restricted to dry subalpine woodland on Mauna Kea Volcano on the island of Hawai‘i because of centuries of habitat degradation by non-native ungulates. Palila are morphologically and behaviorally adapted to consume māmane seeds by grasping seed pods with their feet and opening pods with stout bills and demonstrate limited ability to exploit alternative food resources. This degree of single species dependency is rare among birds and illustrates unique adaptations that also occurred in other Hawaiian species that are now extinct. In mixed-woodland with co-dominant naio (Myoporum sandwicense), Palila spent 1.7–3.9 times longer in māmane than in naio during foraging observations where naio was 1.3–4.6 times as dense as māmane. Naio fruit was readily available, but it comprised proportionally <11% of food items taken by Palila. Although māmane flowers were more abundant than māmane pods throughout this study except at one lower-elevation mixed-woodland site, Palila spent more time foraging on pods than flowers in both māmane woodland and mixed-woodland, but consumed more flowers than pods in mixed-woodland. Insects, which have been reported as an important component of the diet of Palila, were apparently taken rarely in this study. Protecting and restoring māmane in woodlands adjacent to the current range of Palila will benefit their recovery, allowing them to exploit increased food availability in areas of their former range.

Although abnormal or injured legs are not uncommon in Hydrobatidae, they are rarely investigated. We aimed in this study to estimate the frequency of leg abnormalities and determine health status (expressed by leucocyte profile) in molecularly sexed European Storm-Petrels (Hydrobates p. pelagicus) captured on the Faroe Islands. We found that 2.4% of individuals captured during the breding season had some leg abnormalities. Half of the birds with abnormalities had puffinosis-like changes, while the rest were missing some part of the leg. Both types of abnormalities were recorded in the two sexes with similar frequency. The proportion of the birds with leg abnormalities seems to be relatively low compared to other Procellariiformes, and stable over time. Despite the apparent disability of the birds with leg abnormalities, we found no significant effect of abnormality status on the leucocyte profile.

We examined blood smears from 139 Northern Saw-whet Owls (Aegolius acadicus) to ascertain the prevalence of haematozoa in this species during fall migration in eastern North America. Owls were captured with mist nets on the Mohonk Preserve near New Paltz, New York from 1 October to 2 December 2011. We examined blood smears under an optical microscope at 200× and 1000× magnification, and observed four genera of haematozoa, Haemoproteus, Leucocytozoon, Plasmodium, and Trypanosoma, in addition to a genus or genera of microfilarial nematodes, unidentifiable by morphology. We found haematozoa in blood smears from both male and female Northern Saw-whet Owls and in both age groups sampled, i.e., hatching year and after hatching year. Leucocytozoon was the most common parasite, with an overall prevalence of 49.6%. Prevalence of Haemoproteus, microfilaria, Plasmodium, and Trypanosoma was 5.0%, 5.0%, 10.0%, and 2.9% respectively, and overall occurrence of infection was 64%. We found no difference in body condition of individuals compared by age, infection status, or intensity of infection. To our knowledge, this is the first record of Plasmodium in Northern Saw-whet Owls, and the first study to document five genera of haematozoa in Northern Saw-whet Owls during fall migration. Revealing new host–parasite information, this study contributes to the information portfolio of Northern Saw-whet Owls and, thus, may influence future research.

We studied the diet of nestling Spectacled Tyrants (Hymenops perspicillatus) in the southeast Pampas region, Argentina. From November 2012 to January 2013, we used video footage to determine prey items that the parents fed to their chicks. We obtained 54 hrs of recording time to survey 18 nests. We identified a total of 125 prey items, representing 33 different taxa, grouped into four classes: Insecta, Arachnida, Chilopoda, and Amphibia. Insects accounted for 94% of total prey. The most frequent prey items were orthopterans (Caelifera), unidentified lepidopteran larvae, and odonats (Zygoptera). Lepidopterans were numerically the most important prey item in November, odonats in December, and orthopterans in January. Diet of the nestling birds was generalist in terms of the consumption of insects, and the changes in prey consumption during the course of the breeding season support an opportunistic feeding behavior by Spectacled Tyrants.

Information on species' abundances of members of the Family Psittacidae (parrots) is scarce. We determined relative abundances of parrots in nine areas of the Yucatan Peninsula; six sampled during the years 2011–2012, and three during 2008–2010. We counted parrots on 360 plots, calculated relative abundance, and constructed dominance - diversity graphs. Six species were identified in the study areas: Amazona albifrons, Eupsittula nana, Amazona xantholora, Amazona autumnalis, Amazona oratrix and Pionus senilis. The southern Yucatan Peninsula harbored the highest number of species. Overall, E. nana was the most abundant species, although in the southern portion of the peninsula A. albifrons was dominant. Using the abundance values obtained in this research, we can begin to identify and establish new priority sites for parrot conservation within the Yucatan Peninsula and develop new proposals for conservation and sustainable management practices in the region.

During 2005–2010, we observed color bands on adult birds to discover one instance of triple brooding and multiple cases of double brooding in western Yellow-breasted Chats (Icteria virens auricollis) in the south Okanagan Valley, British Columbia (BC), Canada at the northern periphery of their breeding range. In the case of the triple brood, the first and second broods successfully fledged chats but the third brood failed. During the same period, 4.7% of banded females had double broods. Another 32 unidentified females for whom we are confident were the same females who initiated the first brood, also had double broods. If these females are included, 13% of chats had double broods. During 2002–2010, 57.8% first brood nests were successful and during 2005–2010, 69.2% second brood nests were successful.

Laughing Falcons (Herpetotheres cachinnans), are known to feed primarily on snakes, although there are reports in the literature of the falcons feeding on other prey. In the present study in the semi-arid scrublands of the Brazilian Caatinga, two predation events were recorded in which Laughing Falcons captured small-bodied mammals, a marmoset (Callithrix jacchus) and a rock cavy (Kerodon rupestris), both estimated to be approximately 200–300 g in weight. In both cases, the mammals were juveniles; the falcon swooped down to capture the prey in its talons, then it flew off to feed some distance away. While these events suggest a shift in the feeding niche of the falcon in response to local conditions, the number of observations is too small to permit definitive conclusions on this phenomenon.

Ruby-throated Hummingbirds (Archilochus colubris) are common and widespread but little is known about their winter ecology anywhere within their nonbreeding range, and no studies have been conducted on the individuals that now overwinter along the southeastern Atlantic coast of the United States. From 2008–2012, I examined the winter survivability, site fidelity, residency, and age and sex ratios of Ruby-throated Hummingbirds at one location in coastal South Carolina. I investigated whether the wintering population there was migratory or sedentary. Winter site fidelity was 19.4% overall (14.6% for males and 31.6% for females), which is similar to or higher than return rates found in studies near the Gulf of Mexico coast, 300 km to the south. The rate of winter residency was 26.3%. Juvenile sex ratios were significantly male biased, suggesting possible latitudinal sexual segregation, although more study is needed. Only one bird banded during spring, summer, or fall was recaptured during the winter, indicating a probable turnover of birds between summer and winter.

We describe behavioral observations of a bilateral gynandromorph Northern Cardinal (Cardinalis cardinalis) in northwestern Illinois from December 2008 through March 2010. The bird exhibited the typical bright red color of a male cardinal on the left half of its body, and the dull brownish-gray appearance of a female cardinal on the right half. We observed the bird more than 40 days, mostly in the vicinity of bird feeders. It was never paired with another cardinal, was never heard vocalizing, and was not subjected to any unusual agonistic behaviors from other cardinals. These observations are among the most extensive of any bilateral gynandromorph bird in the wild.