SHORT COMMUNICATIONS 
795 
TABLE 1. Means (± SE), ranges, and sample sizes of 
nestling movements of Common Nighthawks within three 
age classes in Grand Teton National Park. Wyoming. 2010. 
Daily nestling movement (ml 
Age(days) 
Mean ± SR 
Range mil 
It 
1-5 
1.57 ± 0.43 
0—4 
15 
6-10 
6.88 ± 0.96 
0-14 
16 
11+ 
16.25 ± 3.39 
5-48 
14 
from analyses due to our inability to relocate 
subsequent use-sites. We observed one case in 
which an egg of a two-egg-clutch was crushed by 
an ungulate and the remaining viable egg moved 
0.5 m from the original nest site. It is unclear 
whether the egg was moved purposefully by the 
adult in response to the disturbance or if it was 
inadvertently moved by the adult Hushing during 
or after the disturbance event (Jackson 2007). We 
did not record any occurrences of egg movement 
at any other nests (// = 7). 
A growth rate curve (Fig. 1) was derived from 
71 measurements of 10 nestlings from six 
different broods. Nighthawk nestlings grew in a 
nearly linear fashion (r* = 0.97. t - 48.6, dl = 
68 . r < 0.001). Common Nighthawk eggs hatch 
asynchronously: however, across broods, second- 
hatched nestlings weighed significantly more than 
the older nestlings at the same age (t = 3.17, df = 
14, P = 0.007). 
Forty-five measurements t/i = 6 nests) of nestling- 
stage movements were obtained from nestlings that 
ranged in age from 1 to 18 days. Older nestlings were 
more likely to move longer distances in a day (r = 
0.66, / = 9.16. df - 43. / J < 0.001; Table 1. Fig. 2). 
We observed two cases in which a likely predation 
attempt was made on two different broods and in 
both cases the nestlings moved nearly twice as far in 
comparison to the largest previous site relocations (9 
to 18 m. and 11 to 21 m). In the first case, a nestling 
was observed to be severely injured, presumably due 
to u predation attempt. In the second case, one 
nestling was depredated. 
FIG. 2. Common Nighthawk nestling movements as a function ([y - 0.0138x‘ - 0.1868x- + 1.2665x1; R- 0.66) of 
chick age. Measurements (/i = 45) were collected for nests with 1 to 18 day-old young in Grand Teton National Park. 
Wyoming. 2010. 
