ale becomes increasingly more receptive and her work is often
interrupted by advances of the male. Copulation occurs frequently from
about the third day of nestbuilding through the first day of
egglaying, a period of four to six days. Male displays and
vocalizations associated with courtship continue through the fourth or
fifth day of incubation.

_Displays and Postures_

The principal courtship displays and postures that were seen
throughout the nestbuilding phase are as follows:

1. Greeting ceremonies. Both birds are crouched from one to five
inches apart. The feathers on one (the male?) are sleeked, and on the
other are fluffed. Fluffing (Morris, 1956:80) denotes partial erection
of the body feathers producing a rounded, unbroken body line and is
not to be confused with ruffling, mentioned in the sections pertaining
to territoriality and pre- and post-copulatory display. Fluffing is
generally considered to be an appeasement display and it is seen in a
variety of situations involving a dominant-subordinate relationship.
Both birds flick wings and tails rapidly and reverse directions on
their perches frequently. A low, rapid _chee_ is uttered during this
performance. This ceremony is repeated often in the first three days
of nestbuilding, but less frequently thereafter. It usually occurs
after building by one or both partners and prior to another trip in
search of nesting material. It lasts from 10 to 50 seconds and is not
immediately followed by any additional courtship activities. Nolan
(1960:228-229) observed mutual displays between periods of violent
sexual chase that suggest that the greeting ceremonies that I have
described are an integral part of pair-formation as well as a
component of continued maintenance of the bond.

2. "Pouncing." The female rapidly quarter-fans and partially depresses
her tail. She utters a high pitched scold (_chee_). The male, from a
perch within two feet of the female, fans the tail fully and depresses
it vertically, and, with mouth open, lunges at the female; or, with
similar tail mannerisms, the abdominal feathers ruffled, the wings
held horizontally, and the primaries spread, he sways from side to
side from four to six times, and then lunges at the female. The male
is silent when he pounces; the _chee_ or the courtship song is emitted
when swaying precedes pouncing. The male strikes the female with his
breast or with his open beak. The female rarely flees although she is
usu