Abstract
Annual survival and recruitment in black brant (Branta bernicla nigricans) have declined since the 1990s, yet aerial surveys of the global population have been stable or even increasing over the past decade. We used a combination of a Lincoln estimator based on harvest information and band recoveries, and marked-unmarked ratios in bag checks in 1 harvest area in Mexico to estimate the number of adults in the population during 1992–2015. We produced weighted means from the 2 kinds of estimates for years in which we had data for both, with weights equal to the inverse of the variance of the individual estimates. We treated the black brant population as consisting of 2 subpopulations. One population consisted of breeding black brant on the Yukon-Kuskokwim Delta (YKD), Alaska, USA, and the other consisted of Arctic (northern Alaska, western Canada, and eastern Russia) breeders, and nonbreeders and failed breeders from the YKD that underwent molt migration to the Arctic. For the global population estimates, we assessed potential bias due to differential marking and harvest of the 2 subpopulations, which was approximately 1%, probably because band recovery rates were similar for the 2 subpopulations. Population estimates declined from 229,980 (average for 1999–2002) to 161,504 (average for 2012–2015). Population estimates based on estimated harvest were variable but more stable in the later years of the study, when larger numbers of brant hunters were included in the sample. We suggest that the combination of Lincoln estimates and bag check data provides a reasonable and cost effective approach to monitoring the population.
| Original language | English |
|---|---|
| Pages (from-to) | 627-637 |
| Number of pages | 11 |
| Journal | Journal of Wildlife Management |
| Volume | 83 |
| Issue number | 3 |
| DOIs | |
| State | Published - Apr 2019 |
Funding
Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the United States Government. We thank all of those that have banded brant in Canada, Russia, and the United States. We also thank those who participated in Pacific Flyway Wing Bees, which generated estimates of species and age composition of the goose harvest, and the numerous individuals that assisted with bag checks in San Quintin, Mexico. The work at San Quintin was supported by the USGS Alaska Science Center (USGS-ASC), Migratory Bird Management Region 7 United States Fish and Wildlife Service (USFWS-Region 7), Arctic Goose Joint Venture, Dorothy and Richard Wheeler, and Ducks Unlimited de Mexico. J. S. Sedinger’s work on the Yukon-Kuskokwim Delta was funded by USGS-ASC, USFWS-Region 7, Ducks Unlimited, the Morro Bay Brant Group, Phil Jebbia (in memory of Marnie Shepherd), and the National Science Foundation (OPP 9214970, DEB 9815383, OPP 9985931, OPP 0196406, DEB 0743152, DEB 1252656). Logistical support was provided by the Yukon Delta National Wildlife Refuge. M. A. Irinaga and L. A. Gullingsrud of CH2M Hill Polar Services provided logistical field support. Additional student support was provided to A. G. Leach and T. V. Riecke by the Dennis Raveling scholarship (California Waterfowl Association) and to T. V. Riecke by Bonnycastle Fellowship in Wetland and Waterfowl Biology, (Ducks Unlimited Canada, The Institute for Wetland and Waterfowl Research). A. G. Leach received support from Great Basin Cooperative Ecosystem Studies Unit (CESU) agreement number G11AC20324 with the ASC, USGS. Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the United States Government. We thank all of those that have banded brant in Canada, Russia, and the United States. We also thank those who participated in Pacific Flyway Wing Bees, which generated estimates of species and age composition of the goose harvest, and the numerous individuals that assisted with bag checks in San Quintin, Mexico. The work at San Quintin was supported by the USGS Alaska Science Center (USGS-ASC), Migratory Bird Management Region 7 United States Fish and Wildlife Service (USFWS-Region 7), Arctic Goose Joint Venture, Dorothy and Richard Wheeler, and Ducks Unlimited de Mexico. J. S. Sedinger's work on the Yukon-Kuskokwim Delta was funded by USGS-ASC, USFWS-Region 7, Ducks Unlimited, the Morro Bay Brant Group, Phil Jebbia (in memory of Marnie Shepherd), and the National Science Foundation (OPP 9214970, DEB 9815383, OPP 9985931, OPP 0196406, DEB 0743152, DEB 1252656). Logistical support was provided by the Yukon Delta National Wildlife Refuge. M. A. Irinaga and L. A. Gullingsrud of CH2M Hill Polar Services provided logistical field support. Additional student support was provided to A. G. Leach and T. V. Riecke by the Dennis Raveling scholarship (California Waterfowl Association) and to T. V. Riecke by Bonnycastle Fellowship in Wetland and Waterfowl Biology, (Ducks Unlimited Canada, The Institute for Wetland and Waterfowl Research). A. G. Leach received support from Great Basin Cooperative Ecosystem Studies Unit (CESU) agreement number G11AC20324 with the ASC, USGS.
| Funders | Funder number |
|---|---|
| G11AC20324 | |
| United States Government Publishing Office | |
| DEB 1252656, DEB 0743152, OPP 0196406, OPP 9214970, OPP 9985931, DEB 9815383 | |
Keywords
- Arctic
- Branta bernicla nigricans
- Lincoln estimator
- Mexico
- Yukon-Kuskokwim Delta
- banding
- black brant geese
- capture-mark-recapture
- population dynamics