Efecto de radio transmisores y anillos de plastilina en la supervivencia de los juveniles de Anas platyrhynchos

Individual markers are essential for measuring survival rates, but few reliable techniques exist for marking young waterfowl. We banded 572-d-old Mallard (Anas platyrhynchos) ducklings from 85 broods with plasticine-filled leg bands in 2006-2007 and marked 82 hatchling Mallards from 43 broods with 1.8-g back-mounted prong-and-suture transmitters in 2006. We compared survival probabilities of marked ducklings and 621 unmarked ducklings from 110 broods where only the female was radio-marked using the nest survival module in Program MARK. The best-supported model recognized deleterious effects of both radiotransmitters (β=-0.82, 85% CI =-1.32 to -0.33) and plasticine bands (β=-0.29, 85% CI =-0.55 to -0.03). Cumulative survival to 30 d of age for unmarked ducklings averaged 0.22 (process variation; σ= 0.11) in 2006 and 0.20 (σ= 0.11) in 2007, whereas 30-d survival of banded ducklings during these 2 yr was 0.14 (σ= 0.09) and 0.13 (σ= 0.09), respectively. Radio-marked ducklings averaged 0.04 (σ= 0.03) cumulative survival in 2006. Although capturing ducklings after they leave nests is not always possible, post hoc analysis showed that marker effects decreased with duckling age and waiting until ducklings were at least 4 d old before marking would have negated these effects. Because marking hatchling Mallards with either radiotransmitters or plasticine bands negatively impacted their survival, we do not recommend these marking techniques for newly hatched ducklings.