Do hunters target auxiliary markers? An example using black brant. Issue 2 (11th January 2022)

• Record Type: Journal Article
• Authors: Sedinger, James S.; Lindberg, Mark S.; Riecke, Thomas V.; Leach, Alan G.; Meixell, Brandt W.; Nicolai, Christopher A.; Koons, David N.
• Is Part Of: Journal of wildlife management. Volume 86:Issue 2(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-11
• Subjects: auxiliary marker -- band recovery -- black brant -- Branta bernicla nigricans -- harvest -- population dynamics -- population estimation -- survival -- targeting; Wildlife management -- Periodicals; Zoology -- Periodicals; 333.954
• DOI: 10.1002/jwmg.22172
• Languages: English
• ISSNs: 0022-541X

Abstract

ABSTRACT: Auxiliary markers play an essential role in understanding migration, movement, demography, and behavior of migratory birds. Use of such markers relies on the assumption that the markers do not affect the traits of interest. Neck collars, among the most conspicuous of markers, substantially affect risk of harvest, and survival even in the absence of harvest. Effects of less‐conspicuous markers, such as colored plastic tarsal bands, are not well understood. We used 30 years (1986–2015) of banding, recovery, and recapture data from the Yukon‐Kuskokwim Delta in Alaska, USA, to assess differences in direct band recovery rates (DRRs) between black plastic and brightly colored plastic bands applied to black brant ( Branta bernicla nigricans ). We also assessed the effect of the color of plastic tarsal bands on annual survival, risks of natural mortality harvest, and fidelity to the breeding colony of adult female black brant. When assessing only DRRs we found that brightly colored bands were recovered at higher rates than black plastic bands in the early 2000s, but DRRs for black bands increased more rapidly through time, resulting in similar DRRs for the 2 band colors at the end of the study. Using a Burnham model structure, our results demonstrated that individuals fitted with colored bands had slightly lower hazards of dying from natural causes or hunting than individuals carrying less‐conspicuous black tarsal bands. Differences on annual probability scales were small and credible intervals broadly overlapped between band types, indicating minimal differences between individuals with different band types; however, we could not resolve all confounding in our study design and we suggest that specific studies directed at assessing marker effects are warranted. We encourage education of hunters about their roles as citizen scientists and the potentially detrimental effect of targeting birds with auxiliary markers. Abstract : We detected minimal differences in vulnerability to harvest and annual survival between black brant fitted with brightly colored tarsal bands versus more cryptic black tarsal bands. Nevertheless, we recommend caution in interpreting demographic estimates based on individuals fitted with auxiliary markers. We also recommend informing hunters about their roles as citizen scientists and the problems caused by targeting individuals with auxiliary markers.