Extra-territorial Movements by Eastern Whip-poor-wills
Pamela D. Hunt
Abstract- In the course of conducting research into the habitat use of the Eastern Whip-poor-will (Antrostomus vociferus), I discovered two males that did not follow the typical pattern of remaining within a restricted territory during the breeding season. Over a six week tracking period, these two birds were detected at five different sites scattered across approximately 250 ha, with three of these sites being used by both birds at least once, sometimes simultaneously. Eight other males tracked in 2010-2012 never exhibited this wandering behavior, and instead remained faithful to territories of 1-12 ha (mean = 4.8). Because male Eastern Whip-poor-wills share in incubation and brooding duties, I assume that neither male had successfully obtained a mate. The reasons for this extra-territorial behavior remain unknown.
Impact of the Four Year California Drought on Select Chaparral Birds
Walter H. Sakai
Abstract- The impact of the four year drought (2012-2015) in California on seven birds breeding in the chaparral habitat of southern California was analyzed. Six species, Spotted Towhee (Pipilo maculatus), California Towhee (Melozone crissalis), Song Sparrow (Melospiza melodia), Bewick’s Wren (Thryomanes bewickii), Common Yellowthroat (Geothlypis trichas), and Lesser Goldfinch (Spinus psaltris), are year-round residents. The seventh, Black-headed Grosbeak (Pheucticus melanocephalus), is a breeding summer migrant. Overall capture rates (birds/100 nh) did not decline until the third and fourth year of the drought (19.9%). The decline in HY birds (productivity) declined 25.5% during the first two years of the drought and 71.7% during the second two years. Some species (Bewick’s Wren, Common Yellowthroat, Lesser Goldfinch) had began having reduced productivity in the first two years of the drought, while other species (Spotted Towhee, Song Sparrow, Black-headed Grosbeak) did not begin to respond until the third year of the drought. The numbers of adult birds generally did not decline until the second two years of the drought (20.8%), while breeding birds declined 36.5% during the second two years. The primary reason for bird population decline was found to be reproductive failure.
The Accuracy of Wing Chord Ranges in Pyle (1997) as Indicators of Sex in North-Central Alberta Populations of Least Flycatcher, Myrtle Warbler, and Clay-colored Sparrow
Rowan L.K. French, Amelie Roberto-Charron, Kenneth R. Foster
Abstract- Wing chord ranges for several species and sexes in Pyle (1997) are primarily based upon measurements of museum study skins. Intended to encompass North America, these ranges provide the sole means of non-invasively sexing monomorphic birds outside of the breeding season. The validity of such ranges for live, individual populations has been little explored.
Beaverhill Bird Observatory and Boreal Monitoring Avian Productivity and Survivorship (MAPS) data for sexed, After-Second-Year Least Flycatcher (Empidonax minimus), Myrtle Warbler (Setophaga coronata coronata) and Clay-colored Sparrow (Spizella pallida) individuals were used to determine the accuracy of sexing through wing chord ranges provided in Pyle (1997). Wing chord ranges developed from Alberta data varied by up to 3 mm from those in Pyle (1997). Despite this, wing chord ranges in Pyle (1997) correctly sexed 81.4% of Least Flycatchers, 95.8% of Myrtle Warblers, and 90.2% of Clay-colored Sparrows. Fisher’s exact test found a significant relationship between sex classifications based upon wing chord ranges in Pyle (1997) and those based upon breeding or feather characteristics for all three species (P<0.001), suggesting consistency between the two methods. However, variations in the reliability of these ranges exist within species. We suggest that banders develop age- and region-specific wing chord ranges to account for geographic variation, or use wing chord ranges in Pyle (1997) only in conjunction with other sexing techniques.