I examined the temporal pattern of migration and tree species preferences of Yellow-rumped Warblers (Dendroica coronata) in relation to tree and food phenology across three spring seasons (2001–2003) at a migration stopover site in east-central Illinois, USA. Foraging Yellow-rumped Warblers used tree species in relation to the date that trees initiated bud break and the date caterpillars were most abundant in trees. The first arrival date of Yellow–rumped Warblers at the stopover site varied with date of bud break; duration of migration through the stopover site ranged from 31 to 47 days. The earliest Yellow-rumped Warbler migrants observed arrived at the stopover site before appearance of many arthropods, and foraged on the temporarily abundant adult stage of the hackberry psyllid (Pachypsylla spp. [Fletcher] [Homoptera]). Later migrants switched to foraging for caterpillars. The proportions of foraging observations among tree species were similar across all 3 years and, each year, tree species used by Yellow-rumped Warblers diversified as spring progressed. Yellow-rumped Warblers are short-distance migrants (most winter in the southern United States); my results indicate these birds may have an advantage over long-distance migrants in view of global climate change as they can arrive early at stopover habitats and exploit resources when they are most available.

We examined habitat characteristics associated with Cerulean Warblers (Dendroica cerulea) in breeding areas on the Cumberland Plateau in eastern Kentucky. Cerulean Warbler distribution was examined in 2004 within a large forest stand and no differences were found between occupied and unoccupied areas. We examined differences between preferred song perches and random points in 2005, and identified three potentially important predictors of Cerulean Warbler habitat: large diameter trees, east-facing aspect, and high shrub cover. Cerulean Warbler habitat selection on the Cumberland Plateau appears to be similar to other well-studied portions of the breeding range. Conservation and management efforts directed toward establishing and protecting large tracts of mature forest, especially those on east-facing slopes, should be a reasonable approach to managing Cerulean Warbler populations in this area.

We studied nest-site selection and nest survival of early successional birds at the Barrens Grouse Habitat Management Area in central Pennsylvania in 2006 and 2007. We compared vegetation at nests to that at sites 30 m distant to examine microhabitat characteristics related to nest-site selection and which characteristics were associated with nest survival. Daily nest survival probability was 0.968 ± 0.006 (SE) for Chestnut-sided Warblers (Dendroica pensylvanica), 0.935 ± 0.014 for Field Sparrows (Spizella pusilla), 0.955 ± 0.011 for Indigo Buntings (Passerina cyanea), and 0.960 ± 0.005 for all species combined. Nest-site selection was best characterized by high woody stem density for Chestnut-sided Warblers, Indigo Buntings, and all species combined. Nest survival increased with woody stem density, indicating that nest-site preferences may be adaptive. Ground cover best predicted nest placement for Field Sparrows but no measured variable affected nest survival for this species. We suggest that severe defoliation by gypsy moths (Lymantria dispar) in 2007 had little effect on nest predation risk for early successional birds.

Anecdotal evidence suggests the endangered Great Hornbill (Buceros bicornis) needs mature, large old-growth trees for nesting. We tested this hypothesis by measuring vegetation characteristics at 24 nest sites in southern India and compared these data with that obtained from equal numbers of unused forest sites. Characteristics significantly different from surrounding forest at hornbill nesting sites were several properties related to size of trees. The nesting habitat characteristics of the species stress the importance of mature forests with emergent trees for nests of the Great Hornbill. Trees used by Great Hornbills for nests, compared to unused trees, averaged 18.5 m taller, 0.85 m greater in diameter, and emerged more above the forest canopy by 12.7 m. Canopy height, canopy cover, and number of large trees >75 cm DBH were greater at nest sites than at unused sites by 5.79 m, 3.15%, and 1.63 trees, respectively.

We examined nesting habitat use of Common Eiders (Somateria mollissima dresseri) breeding on Stratton Island, Maine in 2004 and 2005. Eiders generally avoided low-lying, open vegetation, and nested in dense, structurally complex habitats. The three most common habitat types used were Asiatic bittersweet (Celastrus orbiculata) patches, red raspberry (Rubus idaeus) thickets, and forest (primarily Malus pumila and Prunus virginiana). Nest densities were highest in bittersweet (> 500 nests/ha). Eiders had little nest predation by Larus gulls, and apparent nest success was high in all three habitats (bittersweet: 82–89%, raspberry: 87%, forest: 58–72%). Eiders appeared to select nest sites adaptively to avoid detection or access by predators, although other factors such as nest microclimate, female quality or condition, and energetic demands during incubation may also be important.

I found 15 nests of the Silky-tailed Nightjar (Caprimulgus sericocaudatus mengeli) from 1994 to 2004 at Cocha Cashu Biological Station, Manu National Park, Perú. Females and males shared incubation and brooding duties with females on the nest during the day and males on at night. Nest relief occurred between 0300–0600 and 1800–2100 hrs. Two-egg clutches were placed on bare ground or on leaf-litter in more mature strands of forest. The semi-precocial young were mobile within 24 hrs of hatching and remained in the area with an adult through the fledgling stage. Both males and females feigned injury during incubation and brooding if disturbed. Three nesting sites were used for 5 years and another for 10 years, suggesting strong site fidelity and possibly a strong pair bond among long-lived individuals.

I monitored Great Tinamou (Tinamus major) clutches between February and May 2000–2002 at La Selva Biological Station in Costa Rica, and describe observations on incubation behavior and nest attendance. Incubation lasted 17 days and began after the clutch was completed. Nest attendance during monitoring was high: birds were incubating during 249 nest checks at all incubation stages. Only five of 18 incubating birds that were monitored (34,282 min) with video and photographic cameras left the nest for a combined 257 min. There was no pattern to time of day or length of time when incubating birds left the nest. DNA from seven incubating birds was used to identify gender and all were males. All birds that sat on clutches defended their eggs and subsequent chicks, but were not recorded standing up to turn their eggs. High nest attendance and reduced parental activity at the nest may reduce nest detection by predators.

We present the first detailed information on egg laying, egg temperature (T_egg), and development of attentiveness and incubation in Western Bluebirds (Sialia mexicana). We used miniature infrared CCD video cameras to record egg laying at three nest boxes and validate attentiveness measurements derived from T_egg in seven other nests. Females entered the nest box on egg-laying days between 0522 and 1037 hrs PST and laid an egg on average 11.4 ± 4.3 min later (n  =  11). Warm weather early in egg laying often elevated T_egg above physiological zero (27° C), despite low parental attendance. Females often began roosting in the nest box 2–3 nights before clutch completion, and most birds began steady night-time incubation with the penultimate egg. Attentiveness, mean T_egg, and number of minutes T_egg exceeded 27° C reached their highest values 1 day or night after clutch completion. Western Bluebirds exhibit gradual onset to incubation that is attributable to vagaries of weather and varying patterns of parental attentiveness.

We examined the spatial ecology of breeding Least Bitterns (Ixobrychus exilis) on Squaw Creek National Wildlife Refuge in northwest Missouri using radiotelemetry. We collected 1,585 locations for 60 individuals (28 males, 32 females) during 23 May–2 August 2005 and 6 June-18 July 2006. Pooled data for both males and females, and both years resulted in mean 50 and 95% fixed kernel home range use distributions of 37.6 (n  =  25) and 223.2 ha (n  =  25) for all individuals with ≥30 locations. The mean maximum distance traveled between telemetry observations was 2,147.1 m (n  =  28). There were no differences in home range size or mobility between male and female Least Bitterns, although there were great variations between years with birds in 2006 using home ranges five times larger than those in 2005. Habitat use was disproportionate to availability with birds using sites with cattail (Typha spp.) and arrowhead (Sagittaria spp.) to a greater extent than available in both 2005 and 2006. One of eight pairs monitored successfully reared young, while females of seven other pairs renested with new mates. Apparent nesting success was low due to severe weather events and nest depredation. We did not observe double brooding. Our study demonstrates that Least Bitterns are capable of using much larger home ranges than previously observed.

We studied the distribution of birds breeding within five ecological landforms in Yukon-Charley Rivers National Preserve, a 10,194-km² roadless conservation unit on the Alaska-Canada border in the boreal forest zone. Passerines dominated the avifauna numerically, comprising 97% of individuals surveyed but less than half of the 115 species recorded in the Preserve. We used distance-sampling and discrete-removal models to estimate detection probabilities, densities, and population sizes across the Preserve for 23 species of migrant passerines and five species of resident passerines. Yellow-rumped Warblers (Dendroica coronata) and Dark-eyed Juncos (Junco hyemalis) were the most abundant species, together accounting for 41% of the migrant passerine populations estimated. White-winged Crossbills (Loxia leucoptera), Boreal Chickadees (Poecile hudsonica), and Gray Jays (Perisoreus canadensis) were the most abundant residents. Species richness was greatest in the Floodplain/Terrace landform flanking the Yukon River but densities were highest in the Subalpine landform. Species composition was related to past glacial history and current physiography of the region and differed notably from other areas of the northwestern boreal forest. Point-transect surveys, augmented with auxiliary observations, were well suited to sampling the largely passerine avifauna across this rugged landscape and could be used across the boreal forest region to monitor changes in northern bird distribution and abundance.

Avian communities can benefit from reconstructed herbaceous, strip habitats among agriculture; however, any benefits may be limited by width-dependent factors such as edge effects. We used 2 years of strip-transect surveys to evaluate avian density, richness, and conservation value between non-, narrow (mean width  =  8.2 m), and wide (mean width  =  40.7 m) field borders on intensive row-cropped field margins in the agriculture-dominated Mississippi Alluvial Valley. Wide field borders supported two times more birds (7.0 birds/0.2 ha) than narrow borders (3.6 birds/0.2 ha), which supported six times more birds than no border (0.6 birds/0.2 ha). Mean bird species richness was over five times greater in bordered (0.80–1.10 species/0.2 ha) than non-bordered margins (0.14 species/0.2 ha), but was largely uninfluenced by border width. We documented more bird use of agricultural fields and wooded fencerows adjacent to bordered than non-bordered margins. Red-winged Blackbirds (Agelaius phoeniceus) and Dickcissels (Spiza americana) had the strongest positive response to field border presence and width. Wide borders attracted high densities (2.0 birds/0.2 ha) of Dickcissels, an edge-sensitive species, suggesting the conservation potential of herbaceous vegetation patches <50 m of wooded edges for grassland birds. Extensive implementation of field borders, particularly of enhanced width, may contribute substantially to grassland bird conservation strategies in intensive, agricultural landscapes, although confirmation of these benefits requires additional demographic information.

Detailed accounts of molt and breeding cycles remain elusive for the majority of resident tropical bird species. We used data derived from a museum review and 12 years of banding data to infer breeding seasonality, molt patterns, and age and gender criteria for 27 common landbird species in northeastern Costa Rica. Prealternate molts appear to be rare, only occurring in one species (Sporophila corvina), while presupplemental molts were not detected. Most of our study species (70%) symmetrically replace flight feathers during the absence of migrant birds; molting during this period may limit resource competition during an energetically taxing phase of the avian life-cycle.

We categorized and quantified the complete vocal repertoires of breeding adult auklets (Aethiini, 5 species) in their breeding areas to provide a baseline for comparative study of the structure and function of vocalizations within this monophyletic group of seabirds. We recognized 22 call types across species and 3–5 call types for each species. Calls were characterized by one to five frequency modulated, harmonically rich note types arranged sequentially in varied combinations. Frequency attributes varied more than temporal attributes within and across species. Repertoires and display complexity of nocturnal and diurnal species did not differ consistently. We recognized two major forms of vocal display: alternating arrangement of note types (Cassin's Auklet [Ptychoramphus aleuticus] and Parakeet Auklet [Aethia psittacula]); and sequentially graded arrangement of note types (Least Auklet [A. pusilla] and Whiskered Auklet [A. pygmaea]). One species' repertoire (Crested Auklet [A. cristatella]) was composed of a mix of the two forms of display. There were vocal homologies in frequency modulation of notes, arrangement of notes, and note type composition of displays. Our analysis revealed vocal similarities between: (1) two species not normally grouped together (Cassin's and Parakeet auklets); and (2) Whiskered and Crested auklets, which have been suggested previously to be closely related.

We studied foraging behavior of Tufted Tit-Tyrants (Anairetes parulus) in Matorral (shrubland) habitat of northcentral Chile. This species is a generalist insectivore feeding in most shrubs of Matorral habitat at our study site, although they favored three of the dominant plant species. Their foraging is typical of small tyrannid flycatchers, using rapid perch gleans coupled with hover gleans and supplemented by flycatching. They use relatively long search periods (3–5 sec) followed by rapid gleans, which is typical for small tyrannids. Their active foraging (3.1 ± 1.8 prey attacks/min) coupled with a longer search time distinguishes them from parids or regulids of the Holarctic with which they often are compared. They generally forage singly or in pairs and aggressively defend what appears to be foraging territories in winter and summer. Densities of Tufted Tit-Tyrants at our study site were higher than reported in other studies from Chile and Argentina, presumably reflecting resource availability.

We developed time-activity budgets for 286 Yellow-bellied Sapsuckers (Sphyrapicus varius) from October 2005/2006 to March 2006/2007 in east Texas bottomland hardwood forests. Behaviors were similar between genders and study sites (P > 0.05), but varied (P  =  0.008) between years. Sapsuckers spent more time foraging upon arrival in wintering areas and during morning throughout the study periods. Deviation from monthly average low temperature was an important (P  =  0.038) covariate during the second study year, when sapsuckers increased time spent foraging during colder than average temperatures and increased time perching on days with warmer than average temperatures. Sapsuckers partitioned about half their time foraging (early in the day) and half their time perching (later in the day). Sapsuckers may have little physiological need for drastic behavioral adjustments to successfully meet nutritional demands during winter in areas with mild climates.

We studied summer use of high elevation lakes by American Dippers (Cinclus mexicanus) in the Trinity Alps Wilderness, California by conducting repeated point-count surveys at 16 study lakes coupled with a 5-year detailed survey of all available aquatic habitats in a single basin. We observed American Dippers during 36% of the point-count surveys and found birds at 10 of 16 study lakes. Over 90% of the American Dipper sightings were in lentic habitats in Deep Creek Basin. Bird presence at a lake was positively correlated with steep rocky littoral zones and high densities of caddisfly (Trichoptera) larvae. We also observed numerous successful foraging bouts on juvenile life stages of lentic-breeding amphibians. We did not find any nests at the lakes but did observe juvenile dippers. American Dippers are highly adapted to flowing waters, and our findings coupled with incidental observations from the literature and other researchers suggests that high elevation lentic waterbodies have been largely overlooked as a seasonal niche for migrant dippers.

There are few published data on annual survival and no reports of lifetime reproduction for breeding Cooper's Hawks (Accipiter cooperii). Breeding males (n  =  105) in central and southeastern Wisconsin had an annual mortality rate of 19%, or a survival rate of 81% for birds ≤10 years of age. We did not detect significant differences in mortality rates between urban and rural habitats, nor between the earlier 13 years and later 13 years of this study. Male Cooper's Hawks produced from zero to 32 nestlings during their lifetimes. Body mass or size appeared unrelated to annual survivorship and lifetime reproduction, although lifetime reproduction was correlated strongly with longevity of breeding males. Fifteen of 66 males (23%) produced most (53%) of the nestlings. Our studies occurred in an area where breeding populations may be increasing with some of the highest reported productivity indices and nesting densities for this species. Habitat used for nesting on our Wisconsin study areas may be less important for survivorship and lifetime reproduction than acquisition of a nesting area in which a male will breed throughout his life.

Linnaeus (1766) proposed Certhia pinus based on two different entities, the Blue-winged Warbler (Vermivora pinus) and the Pine Warbler (Dendroica pinus). The confusion was noted by Wilson (1808–1814) who restricted Latham's (1790) Sylvia pinus, based on C. pinus, to the Pine Warbler (in 1811) and proposed, as a new species (in 1810), S. solitaria, for the Blue-winged Warbler. Wilson's effective lectotypification, long ignored, following which Bonaparte (1824) unequivocally restricted C. pinus to the Pine Warbler, has resulted in misapplication of C. pinus. The correct name of the Pine Warbler should be Dendroica pinus (Linnaeus) and not D. pinus (Wilson) as in modern lists. Wilson's Sylvia solitaria is unfortunately preoccupied by Sylvia solitaria Lewin 1808 ( =  Origma solitaria, the Rockwarbler of Australia). A new scientific name is provided here for the Blue-winged Warbler because no other is available.

New data are presented on the phylogenetically informative plantaris muscle in the Drepanidini. The primitive condition (presence) corroborates the basal placement of the creepers of the genera Oreomystis. and Paroreomyza. The derived condition of the plantaris (absence) was found in the Hawaii Creeper (Loxops mana), previously considered by some to be congeneric with Oreomystis, and agrees with other evidence placing that species in Loxops. The Hawaii Akepa (L. coccinneus), Anianiau (L. parvus), and Kauai Amakihi (L. stejnegeri) also lack the plantaris. This condition still appears to define a monophyletic group within the Drepanidini.

The genus Thryothorus is a wide spread genera in the Neotropics and nesting information is known for 85% of the species. I found four nests of the Moustached Wren (Thryothorus genibarbis) that were dome and bulky ball-like structures with a side entrance. All nests contained two white eggs with reddish-brown blotches. Daily nest attentiveness was 58.0% and average egg temperature was 32.5° C. Incubation behavior varied among nests and also throughout the incubation period, especially during early stages.

I describe nests and eggs of the White-bellied Seedeater (Sporophila leucoptera) in Brazil. Nests (n  =  5) were cup-shaped and built of thin grass roots and spider web silk with thin walls allowing eggs and young to be seen through them. Nests were in trees (2.5–4.5 m above ground) and close to water. Eggs (n  =  3) were white with black and brown spots concentrated at the large end and measured 19.2 × 13.0 (1.7 g), 18.7 × 13.3 (1.8 g), and 18.8 × 13.9 mm (1.8 g). Both parents fed nestlings, but only females incubated. The White-bellied Seedeater is not presently endangered, but many local populations have been extirpated because of intense commercial trapping and habitat loss. Additional knowledge on the ecology and breeding biology of seedeaters is urgently needed for development of effective conservation plans.

Pogonotriccus bristle tyrants are a small group of flycatchers for which few data on nest architecture are available. I describe the nest of Marble-faced Bristle Tyrant (P. ophthalmicus) from eastern Ecuador. The nest was an oven-shaped, mossy ball with a hooded side entrance attached by the back to the trunk of a large tree. I discuss aspects of nest architecture, composition, and placement which may prove useful for resolving phylogenetic hypotheses within the Leptopogon-Pogonotriccus-Pseudotriccus clade of pipromorphine flycatchers. These characters, in particular nest attachment and construction, support a close relationship between Pogonotriccus, Pseudotriccus, and Corythopis. The switch from draping material to stuffing material during construction may be a key innovation uniting these genera.

The Black-cheeked Ant Tanager (Habia atrimaxillaris) is endemic to the Osa Peninsula on the south Pacific coast of Costa Rica. There is little knowledge of the natural history and especially the reproductive habits of this species. We describe the nest and eggs of the Black-cheeked Ant Tanager based on observations of three nests near Puerto Jiménez, Puntarenas, Costa Rica. The nests and eggs were similar to other species of Habia supporting previous work suggesting relationships within Habia.

Reports of adoption in birds are widespread, but few studies report rates of adoption or possible mechanisms for this phenomenon, particularly in the Order Galliformes. We report incidents of adoption in Rock Ptarmigan (Lagopus muta) and White-tailed Ptarmigan (L. leucura) from two sites in western Canada. Adoption rates for White-tailed Ptarmigan on Vancouver Island, British Columbia, and the Ruby Ranges, Yukon Territory were 13% (n  =  16 broods) and 4% (n  =  27), respectively, while rates for Rock Ptarmigan were 14% (n  =  29) in the Ruby Ranges. Low brood densities may result in lower rates of adoption for ptarmigan.

Trichomoniasis is a digestive tract disease caused by ingestion of the protozoan Trichomonas gallinae. This disease can be a significant source of mortality. No deaths of nestlings could be attributed to trichomoniasis in Cooper's Hawks (Accipiter cooperii) breeding in urban and rural environs in Wisconsin, North Dakota, and British Columbia. We detected T. gallinae in four (5.2%) of 77 nestling Cooper's Hawks during 2006 and 2007 among 42 urban nests on new study areas in southeast Wisconsin and eastern North Dakota/western Minnesota. All four infected young fledged. We did not detect T. gallinae in 52 breeding adult Cooper's Hawks on two urban study sites, nor in 28 migrant hatching year (n  =  24) and adult (n  =  4) Cooper's Hawks at Hawk Ridge Nature Reserve, Duluth, Minnesota in 2006–2007. Overall, we detected T. gallinae in only 2.5% of 157 Cooper's Hawks in northcentral North America. These results suggest a low prevalence of T. gallinae in Cooper's Hawks in the northern part of this hawk's breeding range.

Nocturnal migration is accompanied by sleep loss likely dependent upon the length of the migratory flight. Migrants may minimize the effect of sleep deficit by inserting brief naps into their daytime activities. On 25 April 2006, I observed daytime sleep-like behavior by a radio-marked male Hooded Warbler (Wilsonia citrina) at a coastal stopover site in southwestern Louisiana. The bird likely completed a flight across the Gulf of Mexico a few hours before the observation and departed from the stopover site the evening of the day of arrival. To my knowledge, this is the first reported field observation of daytime sleep behavior in a neotropical landbird migrant. The behavior exhibited in the field was consistent with behavioral characteristics of daytime sleep observed in captive migrants.

We describe a commensal relationship between Double-crested Cormorant, (Phalacrocorax auritus) and a southern stingray (Dasyatis americana). Three cormorants were observed closely following a large southern stingray in a shallow turtle grass (Thalassia testudinum) bed near Long Key, Florida and feeding upon a small fish disturbed by the stingray's benthic foraging. This represents an example of a commensal relationship in which one participant benefits while the other is unaffected.

Plant entanglement in North America is reported for 25 bird species, of which 56% are affected by burdock (Arctium spp.; one of 15 plant taxa). To our knowledge, we are the first to document mortality of the Least Flycatcher (Empidonax minimus) by snaring in burdock (A. minus).

We summarize the history of the varied practices of hyphenating compound English names of birds to highlight taxonomic relationships. English names do not and can not reflect phylogenetic relationships of birds very well, however lofty that ideal. Instead, English names of birds are driven more by tradition than by modern systematics; the consequence is that well-intentioned hyphenation practices misrepresent phylogenetic relationships too often to be helpful. We urge ornithologists to work together to simplify the use of hyphens as one small step towards improved standardization of English bird names.