Rb. Lanctot et al., Do male breeding displays function to attract mates or defend territories?The explanatory role of mate and site fidelity, WATERBIRDS, 23(2), 2000, pp. 155-164
Many shorebirds show elaborate breeding displays that include aerial flight
s and ground displays accompanied by song. The mate attraction hypothesis s
uggests that breeding displays function to attract mates and maintain pair
bonds, whereas the territory defense hypothesis suggests breeding displays
function in defining and defending nesting and feeding territories. We test
ed these hypotheses in the Western Sandpiper (Calidris mauri) by contrastin
g the duration and level of male breeding displays among pairs that differe
d in their mate and site fidelity. As predicted by the mate attraction hypo
thesis, males performed the highest number of song sequences during pair fo
rmation, and males paired with their mate of a prior year sang less than ma
les paired to new mates. Further, site-faithful males mated to a new but ex
perienced mate displayed significantly more than remated males or males new
to the area. This suggests a male's prior familiarity with an area and his
neighbors does not lessen his display rate as was predicted under the terr
itory defense hypothesis. Limited support for the territory defense hypothe
sis came from observations of males performing breeding displays with neigh
boring males along nest territory boundaries. This behavior was short-lived
, however, as males abandoned nesting areas after pair-formation and used a
djacent or disjointed feeding areas during egg-laying and incubation. Male
aggression (i.e., aerial and ground chases), as opposed to breeding display
s, appeared to be the principal means of maintaining territory boundaries.
Indeed, the rate at which males chased other males remained fairly constant
and high throughout the breeding season. Male chasing behavior may also se
rve as a paternity guard to protect against extra-pair copulations. Our stu
dy also found that a female's prior breeding experience in an area correlat
ed with a reduced display rate by her mate, particularly if that mate was n
ew to the area. This indicates female characteristics may not only drive ne
st initiation, as has been shown in other studies, but are important in det
ermining the duration and extent of male display.