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Green-winged Teal With Plastic Nasal Saddles Had Lower Estimated Annual Survival in a Study of 11,874 Birds

Male Green-winged Teal spreading its wings on water in France
Research · Other research

Green-winged Teal (Anas crecca) fitted with plastic nasal saddles had lower estimated annual survival than birds marked only with conventional leg rings in a French study published in January 2026. Researchers analysed 11,874 teal banded between 2002 and 2021 to test whether the conspicuous individual markers affected the demographic estimates they were intended to improve.

Of the 11,874 marked birds, 6,770 — 57.0% — also received a plastic nasal saddle. Annual survival was estimated with multistate capture–mark–recapture models using each bird’s history of live recaptures, resightings and dead recoveries. It is therefore an estimated probability of surviving from one year to the next, not simply the percentage of marked birds later seen alive. Estimated annual survival was lower in saddled birds in every age and sex class. Among saddled birds, the lowest estimate was about 30% for hatch-year females and the highest about 45% for after-hatch-year males; estimates for birds carrying leg rings only ranged from about 44% to 53%.

Nasal saddles improved identification but not survival estimates

The saddles made live birds easier to identify without recapture, but including these live resightings did not improve the precision of annual survival estimates. The mechanism behind the lower survival remained uncertain; the authors discuss several possible costs of the markers, including altered vulnerability to hunting.

The authors recommend rings for survival monitoring

For long-term demographic monitoring, the authors therefore recommend abandoning nasal saddles when the sole objective is to estimate survival. They note that the markers may still have value in shorter-term studies that require repeated individual identification, but argue that this must be weighed against their apparent survival cost.

Sources and image credit

  1. Guillemain, M., Gelin, M., Plaquin, B., Gregorczyk, E., Champagnon, J., & Bacon, L. (2026). Nasal saddles reduce survival rate in Eurasian teal. Journal of Wildlife Management, 90, e70181. https://doi.org/10.1002/jwmg.70181Primary research article first published 21 January 2026. Multistate capture–mark–recapture models used 11,874 Eurasian teal banded in France from 2002–2021; 6,770 (57.0%) also carried plastic nasal saddles. Estimated annual survival was lower in saddled birds across all age and sex classes, while incorporating live saddle resightings did not improve the precision of survival estimates. The authors recommend abandoning nasal saddles when the sole goal is long-term demographic monitoring.

Image: Hobbyfotowiki / Wikimedia Commons — male Eurasian teal / Green-winged Teal (Anas crecca) at Réserve Ornithologique du Teich, France, 6 February 2020; representative French species image; cropped to 16:9 · CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ · Source

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