SURVIVAL OF NORTHERN PINTAIL DUCKLINGS ON THE YUKON-KUSKOKWIM DELTA, ALASKA

We studied survival rates of Northern Pintail (Anas acuta; hereafter p intail) broods and ducklings along the lower Kashunuk River on the Yuk on-Kuskokwim Delta, Alaska. Survival rates were determined for 770 duc klings in 111 broods. Brood sizes at hatch were smaller in 1993 versus 1991 and 1992. Duckling survival rates were lower than those reported in previous studies and differed among years. Survival rates of duckl ings declined with hatching date at a rate of 0.6% per day. Most morta lity occurred during the first 10 days after hatch. Duckling survival rates were correlated with reported annual and seasonal variation in n esting success. This covariation probably results in large geographic and annual fluctuations in pintail production on the Yukon-Kuskokwim D elta. Early nesting pintails had better nesting success and duckling s urvival, which may offset higher nutritional costs of early nesting th rough higher recruitment.