Ga. Paquette et al., EFFECTS OF TRANSMITTERS ON REPRODUCTION AND SURVIVAL OF WILD MALLARDS, The Journal of wildlife management, 61(3), 1997, pp. 953-961
Radiotelemetry is an important tool in many studies of waterfowl ecolo
gy and management, but some studies have indicated that harnessed-radi
opackages affected the behavior and survival of marked birds. Transmit
ters attached mid-dorsally with sutures, glue, and a subcutaneous, sta
inless steel anchor-shaped wire (hereafter anchored backpacks) may eli
minate such problems. Therefore, we compared various measures of repro
duction and survival rates of wild mallards (Anas platyrhynchos) radio
marked with abdominal implants and anchored backpacks at 5 study sites
located in the aspen-parkland biome of the Prairie Pothole Region of
Canada. We also compared our tracking ability between abdominal implan
ts and anchored backpacks and determined retention time of anchored ba
ckpacks. Females with anchored backpacks devoted significantly fewer d
ays to egg laying and incubation and initiated fewer nests than did fe
males with implants. At one site, females with backpacks had significa
ntly lower survival rates than females with implants. At 3 of the rema
ining 4 sites, females with anchored backpacks had lower survival rate
s than females with implants, but these results were not significant.
We detected no difference in our tracking ability between anchored bac
kpacks and abdominal implants (63 of 136 [46%] with anchored backpacks
, and 140 of 319 [43%] with implants were monitored successfully from
the time they were trapped to 30 June at each site). Two anchored back
packs were known to have fallen off and 11 were suspected to have fall
en off, out of 198 backpacks (average retention time for anchored back
packs was 43 +/- 5.8 days for those that lost their transmitter). Our
results suggest that anchored backpacks may have negatively affected r
eproduction and survival rates of wild mallards.