The Prelaying Interval of Emperor Geese on the Yukon-Kuskokwim Delta, Alaska

• Published in: The Condor
• Main Authors: Hupp, Jerry W., Schmutz, Joel A., Ely, Craig R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2006
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Kuskokwim; Alaska; Yukon
• Online Access: http://dx.doi.org/10.1093/condor/108.4.912; http://academic.oup.com/condor/article-pdf/108/4/912/29715243/condor0912.pdf

Abstract Abstract We marked 136 female Emperor Geese(Chencanagica) in western Alaskawith VHF or satellite (PTT) transmittersfrom 1999 to 2003 to monitor their spring arrivaland nest initiation dates on the Yukon Delta, andto estimate prelaying interval lengths once at thenesting area. Ninety-two females with functionaltransmitters returned to the Yukon Delta in thespring after they were marked, and we located thenests of 35 of these individuals. Prelayingintervals were influenced by when snow melted inthe spring and individual arrival dates on theYukon Delta. The median prelaying interval was15 days (range = 12–19 days) in a year when snowmelted relatively late, and 11 days(range = 4–16 days) in two warmer yearswhen snow melted earlier. In years when snow meltedearlier, prelaying intervals of <12 daysfor 11 of 15 females suggested they initiated rapidfollicle development on spring staging areas. Theprelaying interval declined by approximately0.4 days and nest initiation date increasedapproximately 0.5 days for each day a femaledelayed her arrival. Thus, females that arrivedfirst on the Yukon Delta had prelaying intervals upto four days longer, yet they nested up to fivedays earlier, than females that arrived last. Theproximity of spring staging areas on the AlaskaPeninsula to nesting areas on the Yukon Delta mayenable Emperor Geese to alter timing of follicledevelopment depending on annual conditions, and toinvest nutrients acquired from both areas in eggsduring their formation. Plasticity in timing offollicle development is likely advantageous in avariable environment where melting of snow cover inthe spring can vary by 2–3 weeksannually.