An effective nest trap for female Yellow-headed Blackbirds

ABSTRACT.    Capturing breeding female blackbirds using mist nets and food-baited traps can be challenging because nets are difficult to set in wetland habitats and females feed preferentially on insects. Given the problems associated with other trapping methods, we designed a highly effective nest trap that allowed us to successfully capture targeted female Yellow-headed Blackbirds ( Xanthocephalus xanthocephalus ) at our wetland study sites in North Dakota. From 15 May to 16 July 2004, we captured 56 of 59 (95%) targeted females during incubation and eight of 18 (44%) targeted females with nestlings, and were also able to recapture 12 of 16 females (75%). Based on these results, we recommend using our trap to capture female blackbirds during incubation rather than during the nestling period. The nest trap is easy and inexpensive to construct and is light and easy to carry through dense wetland vegetation. In addition, the trap's large diameter and wire construction provide the flexibility needed to trap at sites where the density of vegetation varies. This trap has also been used to capture female Red-winged Blackbirds ( Agelaius phoeniceus ) and could potentially be used to trap females of other species of wetland-breeding icterids, including Common Grackles ( Quiscalus quiscula ).