|Sunrise from the Amherst Trail, Mt. Mansfield (photo by S. Faccio)|
Interestingly, numbers of male Blackpolls captured on Mansfield this season were above "normal" (an elusive term in biology), with 23 ending up in our mist nets. This number was likely inflated through our use of vocal playbacks to lure birds into nets for geolocator attachment, but most of these were eventually captured passively during the course of the season. For comparison, during 2000-2012, we mist netted an average of 14.1 male Blackpolls annually, adjusted to 15.7 (range 8-22) when discounting the outlier years of 2002 and 2004. Whatever factors accounted for the steep decline in female captures during 2013, males appear not to have been similarly affected.
|Steve Faccio and Brendan Collins attaching a|
geolocator to a male Blackpoll Warbler
Whatever the reason for 2013's drop in female Blackpolls on Mansfield (and we may never know), we can only hope it's not a sign of deeper problems. Blackpoll Warbler is a species of continental conservation concern for groups like Partners in Flight, and VCE's annual monitoring on Mansfield is one of the only projects that tracks this species' breeding population dynamics. We'll know more a year from now, both after another season of monitoring and from recovery of the light-level geolocators we applied to 18 males and 1 female this summer.
|Female Blackpoll Warbler with geolocator (photo by K. McFarland)|
Encouragingly, we mist-netted two juvenile Blackpolls during our final July session, indicating that the species' nesting season wasn't a total bust. The VCE crew will return to Mansfield for our annual "mop-up" visit in mid-September. We'll hope to find some Blackpolls still present and to attach our one remaining geolocator to an adult before it departs for points far south. We'll report back then, and we expect to have some fascinating insights to share a year from now. Stay tuned.