Egg flotation estimates nest age for Pacific and Red-throated Loons

Waterbirds
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Abstract

We used Pacific Loon (Gavia pacifica) and Red-throated Loon (G. stellata) nests with known ages to gauge the efficacy of egg flotation for determining nest age in coastal Alaska. Egg flotation accurately estimated nest age for both species; the mean ± 1SD difference between known age and age determined with egg flotation was - 0.05 ± 2.00 d and -0.02 ± 1.63 d for Pacific and Red-throated Loons, respectively. Day of nest initiation did not influence the relationship between known nest age and nest age estimated with egg flotation, indicating incubation period was not shortened in nests initiated later in the season. Additionally, we found no difference in the ability of egg flotation to estimate nest age between two widely dispersed study sites for Pacific Loons, and only a small difference between two of three widely dispersed study sites for Red-throated Loons. Thus, our described relationships between egg flotation categories and nest age should be broadly applicable for these holarctic species. We conclude that for Pacific and Red-throated Loons, egg flotation is a useful technique for determining nest age in the field to better monitor nest fate, and to quantify nest age effects on nest daily survival rate.

Publication type Article
Publication Subtype Journal Article
Title Egg flotation estimates nest age for Pacific and Red-throated Loons
Series title Waterbirds
DOI 10.1675/1524-4695(2007)30[207:EFENAF]2.0.CO;2
Volume 30
Issue 2
Year Published 2007
Language English
Contributing office(s) Alaska Science Center
Description 7 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Waterbirds
First page 207
Last page 213
Online Only (Y/N) N
Additional Online Files (Y/N) N
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