The Ethiopian Highlands are divided by lowland biogeographic barriers, including the Blue Nile Valley (BNV) and Great Rift Valley (GRV). We show that the GRV is a more pronounced phylogeographic break than the BNV for 6 focal passerines. Previous research suggests that the BNV greatly shaped phylogeographic patterns in relatively sedentary montane taxa such as frogs and rodents...
Despite the increased frequency with which wildfire smoke now blankets portions of world, the effects of smoke on wildlife, and birds in particular, are largely unknown. We used 2 decades of banding data from the San Francisco Bay Bird Observatory to investigate how fine particulate matter (PM2.5)—a major component and indicator of wildfire smoke—influenced capture rates and body...
Trait polymorphisms are a perennially popular topic of study in ecology and evolutionary biology. Plumage polymorphisms occur broadly in birds, with a particularly high rate among the raptors. The regularity of this heritable, melanin-based trait in raptors has prompted research into its potential connections to aspects of life history such as immune response, foraging ecology...
This is the 24th supplement since publication of the 7th edition of the Check-list of North American Birds (American Ornithologists’ Union [AOU] 1998). It
Richard (Dick) L. Zusi, Emeritus Curator of Birds at the Smithsonian Institution’s National Museum of Natural History (NMNH), died on January 15, 2024, in
James (Jim) Baird, a tireless conservationist who served in several key roles in the Massachusetts Audubon Society (Mass Audubon) for more than two decades
Gerald (Gerry) Francis Shields, a remarkably dedicated student, teacher, and scientist, died unexpectedly on 2023 April 1. Gerry published broadly on the t
For most birds that exhibit delayed dispersal (remaining on the natal territory rather than dispersing to seek a breeding opportunity), siblings appear free to stay or leave the natal area. However, in rare cases, delaying dispersal is determined via conflict among siblings, with the dominant individual remaining on the natal territory. We used radio-tracking to examine brood...
Developing conservation and recovery strategies for Nearctic–Neotropical migratory songbirds requires key research because population-limiting factors remain unknown for many species. In particular, the stationary nonbreeding period (sometimes referred to as overwintering) encompasses 6–8 months of the full annual cycle. We conducted a systematic review to assess what is known...
The “island syndrome” refers to similarity in the biology of island organisms, but its generality is questionable, as the scope of species and traits examined are often limited. Here, I show that birds breeding exclusively on islands (breeding island endemics) evolved smaller clutches, using a dataset of 4,530 bird species. Using an inclusive definition of a breeding island...
Most of our knowledge of secondary hole-nesting birds comes from populations breeding in human-provided nestboxes, yet these might differ from natural cavities in a number of parameters, including internal dimensions or microclimate, leading to differences in reproductive ecology. Here, we demonstrate differences in plumage coloration, an important visual signal of individual...
We assessed correlations between speciation rate and bill morphology in an ecologically diverse and continental-scale songbird radiation, the tanagers (Thraupidae). Our analyses showed that bill size, shape, and their evolutionary rates are not correlated with speciation rate. However, we did find evidence that each axis of variation in bill morphology diversifies at speciation...
Bird species that undertake irruptive migrations are good candidates for assessing density-dependent effects on stopover ecology because the number of birds using stopover sites varies considerably from year to year. Using morphometric data from a 9-year banding program and radiotelemetry (n = 25 females), we found that increases in the annual density of Northern Saw-whet Owls...
Richard Charles “Dick” Banks, a major contributor to North American ornithology during the latter half of the 20th century, died peacefully at his home in Alexa
Many avian species breed in enclosed nests that may provide better protection against predation and climatic conditions compared to open nests and are generally associated with larger clutch sizes and slower offspring growth. Here we show that different enclosed nesting strategies are each linked to behaviors with very different costs and benefits on a macroevolutionary scale...
Our understanding of Amazonian biogeography is quickly increasing, catalyzed by the growing use of genomic datasets, improved knowledge of species distributions, and the accumulation of new data on the geological and climatic history of the region. The high number of species in Amazonia and their intricate patterns of geographic distribution triggered the development of many...
Migrating birds often fly in group formations during the daytime, whereas at night, it is generally presumed that they fly singly. However, it is difficult to quantify group behavior during nocturnal migration as there are few means of directly observing interactions among individuals. We employed an automated form of moonwatching to estimate percentages of birds that appear to...
Hemosporidian parasite communities are broadly similar in Boulder County, Colorado, between two common songbirds––the Black-capped Chickadee (Poecile atricapillus) and Mountain Chickadee (Poecile gambeli). However, Mountain Chickadees appear more likely to be infected with Plasmodium and potentially experience higher infection burdens with Leucocytozoon in contrast to Black...
Reproduction of long-distance migrants can be affected by local conditions on the breeding grounds as well as those encountered during the nonbreeding season through carry-over effects. We show that this is true in Long-tailed Jaegers (Stercorarius longicaudus) because individuals that spent less time flying at sea during winter had a high breeding propensity and a reduced pre...