Timing and duration of stopovers affects propensity to breed, incubation periods, and nest success of different wintering cohorts of red knots in the Canadian Arctic during the Years 2009 to 2016

Joanna Burger; Ronald R Porter; Lawrence Niles; David J Newstead

doi:10.1016/j.envres.2022.114227

Timing and duration of stopovers affects propensity to breed, incubation periods, and nest success of different wintering cohorts of red knots in the Canadian Arctic during the Years 2009 to 2016

Environ Res. 2022 Dec;215(Pt 1):114227. doi: 10.1016/j.envres.2022.114227. Epub 2022 Aug 28.

Authors

Joanna Burger¹, Ronald R Porter², Lawrence Niles³, David J Newstead⁴

Affiliations

¹ Division of Life Sciences, Ecology, Evolution, and Natural Resources, Pinelands Field Station, 604 Allison Road, Piscataway, NN, 08854, USA. Electronic address: burger@biology.rutgers.edu.
² 800 Quinard Court, Ambler, PA, 19002, USA.
³ Conserve Wildlife Foundation of New Jersey, 2 Preservation Pl, Princeton, NJ, 08540, USA; L. J. Niles Associates, LLC, 109 Market Lane, Greenwich, NJ, 08323, USA.
⁴ Coastal Bend Bays and Estuaries Program, 615 N. Upper Broadway, Suite 1200, Corpus Christi, TX, 78401, USA.

PMID: 36044961
DOI: 10.1016/j.envres.2022.114227

Abstract

Recent interest in migratory connectivity of shorebirds leads to examining the role stopovers and connectivity play in reproductive success. Since many shorebird species are declining, there is a need to determine factors affecting reproductive success. We used light records from 104 geolocators recovered from red knots (Calidris canutus rufa) to examine-incubation success as a function of temporal patterns at stopovers, year (2009-2016), and wintering cohort. Geolocators were attached on leg flags, mainly in Delaware Bay (New Jersey) and Texas. Successful incubation in different years ranged from 21 to 76%; from 8 to 43% of knots did not attempt incubation on breeding grounds. This is the first estimate of the number of shorebirds going to the Arctic that did not breed, since all other estimates of success were derived from field studies based on birds that initiated nests. High breeding success (76%) occurred in only one year (2011). Nearly all of knots stopped in Hudson Bay region. Arrival date and time in the Pre-Arctic, arrival on breeding grounds, year, and wintering cohort were associated with successful incubation. The percentage attempting incubation, and the percentage that were successful, varied by wintering cohort. When only the east coast rufa knots are considered, time spent on Delaware Bay showed a significant duration difference. Knots wintering in Texas had the highest propensity to initiate incubation (96%), and the highest incubation success (67%). Of rufa knots using the Atlantic flyway, those wintering in southern South America had the lowest incubation success rate (25%). We discuss the importance of quality of flyways, opportunities for refuelling during migration, and importance of time at stopovers. These data can be used to understand migratory connectivity, distinguish factors affecting reproductive success of long-distance migrants, determine which parts of the annual cycle require protection, and aid in recovery plans for long-distance migrants.

Keywords: Arctic breeding cycle; Calidris canutus rufa; Incubation attempts and success; Migratory connectivity; Red knots.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't

MeSH terms

Animal Migration*
Animals
Birds
Breeding
Canada
Charadriiformes*
Humans
Seasons