The effects of back-mounted radio transmitters on reproductive effort
and return rates of pre-nesting pairs and incubating female Wood Ducks
(Air sponsa) were investigated. Twenty of 22 pre-nesting pairs remain
ed together after capture and radio-marking, but only two females from
radio-marked pairs attempted to incubate, and none were captured in n
est boxes during the subsequent 2-3 breeding seasons. Nest success, du
ckling survival and return rates did not differ significantly between
a sample of females radio-marked during incubation and those leg-bande
d only, but statistical power was low (0.11-0.32). Detrimental effects
of back-mounted radio transmitters may preclude their use in studies
of pre-nesting Wood Duck pairs, but back-mounted transmitters appear t
o have minimal effects on incubating and brood-rearing females.