Laura Erickson's For the Birds

Birds in the News

Birds have been in the news quite a bit lately. After an ice storm ran through Ohio in early January, Ohio Birds had photographs of two Mourning Doves whose tails had been iced up, making flying difficult. An adult female Rufous Hummingbird turned up in the Cincinnati area in late December—it wasn’t the hummingbird at my own feeder, but had been banded the previous year in Georgia. Hummingbird authority and bander Allen Chartier writes, “I have just found out that the adult female Rufous Hummingbird in Cincinnati [city of Montgomery], still coming to a feeder as of (January 11), was originally banded in Forsythe, Georgia (just north of Macon) on January 9, 2003 as an adult female. This bird was hatched at least in June 2002 (month presumed, per banding lab protocol), and possibly earlier. This makes her at least 2 years 7 months old, and in banding terms, at least an after-third-year as of January 1. I have called the homeowner and let her know this information . . . .” Photos of the bird are on the Ohio Birds website. I don’t know how long it remained—it survived the ice storm, and was apparently in a race with another rufous currently residing in Zaneseville, Ohio, for a run at the Ohio late record for this species, which is January 23. The January 23 record was set by a rufous last year in Greenville, Darke County, according to Chartier.

Ohio has also had reports of extremely late Chuck-will’s Widow and Common Nighthawk this winter, and there has been some speculation that these extremely out-of-range birds were taking advantage of torpor to survive—after all, they’re in the same family as the Poor-will, and at least some individuals of that species have spent entire winters hibernating or in extended torpor. Research published in Physiological and Biochemical Zoology in 2004 suggests that the ability to go into torpor has a great deal of individual variation in this family, at least in Whip-poor-wills. Jeffrey Lane from the University of Alberta, and two collaborators, captured 35 Whip-poor-wills near Vermillion, South Dakota, and placed on the birds small radio transmitters that transmitted the birds’ skin temperatures. Birds were tracked throughout the day and their body temperatures recorded. Skin temperature dropping below about 86 degrees Fahrenheit was judged to be indicative of torpor. Using that criterion, four of the 35 birds were found to go into torpor. One individual’s skin temperature even dropped to about 66 degrees. The birds foraged for insects at night, then entered torpor at about 5:30 am, and emerged from the state about 9 am as temperatures rose. Based on their results, the authors suggest that torpor is reserved as a response to extreme stress in this species. They plan additional work to figure out why some individuals enter torpor while others don’t, and what kinds of stresses induce this interesting physiological state.