|Abstract or Summary
- Diurnal time budgets and habitat use patterns of breeding Ugashik marbled godwits
(Limosa fedoa beringiae) were studied on the north-central portion of the Alaska Peninsula
during spring and summer 1995-1996. Marbled godwits were observed from blinds and
behaviors were described for the four phases of the breeding season: pair-formation, egg-laying,
incubation and post-hatching. During pair-formation, males spent the majority of
time performing flight displays (40.2%), most notably the ceremonial flight (30.7%).
Males spent 34.3% of the egg-laying period guarding their mates probably to reduce the
threat of cuckoldry. Females incubated during the daytime and males incubated at night.
Off-duty males were engaged in maintenance activities (49.4%) or were alert/erect
(22.7%). Four marbled godwit nests and the first newly hatched, downy marbled godwit
chicks ever recorded in Alaska were found within the study site. One parent guarded the
chicks which allowed the other to forage in nearby wetlands. Males performed male-exit
flight as they prepared to depart for coastal staging lagoons approximately three weeks after
their chicks hatched. Interspecific and intraspecific hostility peaked during the post-hatching
period although aggressiveness towards neighboring shorebirds decreased.
Godwits may benefit from the aggressive nature of some neighboring shorebirds and more
timid species may receive a similar benefit from nesting close to godwit semi-colonies. The
scattering of nests in loose semi-colonies may reduce predation by offering both nest
concealment and group defense.
Cover types and microhabitat characteristics were compared between sites used by
marbled godwits ("present") and paired sites where no godwits were observed throughout
the breeding season ("absent"), and among sites used for broodrearing, foraging, ground
display and nesting. Logistic regression models predicted the probability of godwit
occurrence or the probability of a godwit broodrearing, foraging, displaying or nesting
based upon significant site features. Results indicate that different cover types were used
for broodrearing, foraging, ground display and nesting, and cover types differed between
present and absent sites. Microhabitat characteristics were different between present and
absent sites, and they varied among the different use sites. The odds of finding a godwit at
a site or the odds of finding a godwit broodrearing, foraging, displaying or nesting
changed with changes in the significant microhabitat characteristics. As the percent shrub
cover increased the odds of finding a brood or a nest increased 2.65-fold and 1.95-fold,
respectively. The vegetation at broodrearing sites was taller (1.6 dm) than the vegetation at
the other use sites, while the vegetation at nest sites was considerably shorter (1.3 dm) and
denser. The probability of finding a godwit foraging increased with increasing forb cover
and water depth, and decreasing shrub and moss cover and site roughness. Godwits used
the periphery of wetlands for ground display. These grassy areas were typically transition
zones between the wetland itself and the drier shrub communities.