Radiomarking brood‐rearing mallard females: Implications for juvenile survival

Radiotelemetry is frequently used to measure habitat use, movements, and survival in birds; presumably, outfitting adult females with radiotransmitters does not influence juvenile survival, but this critical assumption is rarely tested. We evaluated whether the timing or type of transmitter deployed on adult female mallards (Anas platyrhynchos) reduced duckling survival estimates in the Canadian Prairie Pothole Region, 1993–1995. The best-approximating model suggests that, compared with 2 other trap–transmitter combinations, ducklings raised by mallard females trapped prior to nest initiation and outfitted with anchor–suture transmitters had poor survival. The 30-day survival rate of ducklings raised by female mallards equipped with anchor–suture transmitters prior to nest initiation was lower than survival of ducklings attended by females equipped prior to nest initiation with abdominally implanted transmitters or females marked during late incubation with anchor–suture transmitters. Studies of reproductive success deploying anchor–suture transmitters on female waterfowl trapped prior to nest initiation may have biased results because of possible negative consequences to offspring survival. © 2012 The Wildlife Society.