¢ two or three broods, this premise has not been 
stantiated from observations of banded birds in 
nois. Re-use of a successful nest is not proof of 
ible-broodedness. 
Surprisingly, for such an interesting nest struc- 
e, there are no published notes on the nest build- 
phase of the cycle for the barn swallow. Loucks 
ipublished notes, 1890) stated that the nest was 
de of mud and hay, loosely lined with white 
thers. Studies of nest construction in relation to 
types would be of interest. Are barn swallow 
ulations reduced in sandy soil areas? 
For four June nests in southern and northern 
nois, we recorded nest-building periods of 8, 
9, and 12 days. Incubation periods for several 
ts in central and southern Illinois varied from 
to 16 days, most frequently being 15, and nes- 
g life was 16-20 days. Davis (1968) also recorded 
estling period of 16 days. Thus, one nesting cycle, 
luding egg-laying for a four-egg clutch, would 
uire 41-51 days, which is about the interval be- 
en the May and July peaks in egg-laying (Fig. 
, and further indication of double broods. 
Most barn swallow nests receive five eggs. Many 
sive four, and six-egg clutches are not uncommon 
able 1). There is at least one record of a nest 
h seven eggs (Blocher 1926). Clutch size declines 
htly as the season passes (Table 1). The disparity 
the number of five-egg clutches in April and 
y between central and southern Illinois (Table 1) 
uzzling, but sample sizes are small and more data 
needed to determine if the differences are real. 
Nesting success (Table 2) was similar for our 
iples of barn swallow nests in central and south- 
Illinois (65-70 percent of eggs produced fledge- 
8), but the sample for northwestern Illinois 
wed very low success (only 21 percent). Larger 
ples of nests and more years of study are needed 
how whether there is truly such marked regional 
ation in nesting success of barn swallows. We 
not account for the poor success observed in the 
thwest on any quantitative basis, because of the 
ll sample. We saw one active barn swallow 
t usurped by house wrens, as did Schafer (1916) 
» in the same region. House sparrows occupied 
ew inactive swallow nests in all regions. More 
's fell and more eggs disappeared in the north- 
TABLE 1.—Clutch sizes of barn swallows in Illinois. 
ion Months Number 
of Nests 
th June-July yas 
tral April-May 21 
une-Jul 82 
June-July 
h April-May 26 
June-July 30 
TABLE 2.—Fledging success of barn swallows. 
ee a ee 
Percent Fledged 
Number Seat 
Region Year of Nests Nests Eggs 
Northwest 1968 17 26 21 
Central 1969 47 74 70 
South 1967 51 70 65 
west than in the other regions. No other causes of 
nest failure have been recorded. The question of 
early-season versus late-season nesting success also 
needs quantitative study. 
Davis (1968) has provided the only Illinois data 
on the care and feeding of young barn swallows in 
the nest. He observed that the adult birds made 
between 12 and 31 feeding trips per one-half hour, 
and he estimated that the adults made 626 trips per 
day to feed a brood of five 10-day-old nestlings. 
He captured the adults and observed that the food 
they were carrying was flies (species not reported) , 
a minimum of five per trip. 
Fall Migration 
Some barn swallows remain near their nesting 
areas (barns, bridges, etc.) weeks after the last 
young have fledged, but generally the departures of 
swallows from local colonies can be detected during 
late July and August, even though the birds may 
not leave all at once. We have seen active migration 
as early as July 23 in northern Illinois, and migra- 
tion flights have been observed widely in August. 
Our observations are much like those of Barnes 
(1933) who described the migration as a continuous 
passage of birds southward, singly, in pairs, and in 
small groups. We have also seen more concentrated 
migrations, involving hundreds of birds passing in a 
few minutes, particularly along the Mississippi val- 
ley in August. Such migrations often involve more 
than one species of swallow. In contrast to the 
circling foraging flights, the migration flights are 
straight, and the flight directions we have recorded 
were south (mainly) and southwest. All of the 
flights we have observed were probably within 250 
feet of the ground, but flights at higher altitudes 
could easily be overlooked. ‘There are no data on the 
timing of the flights through the day, and we do not 
Percent of Nests by Clutch Size 
Average 
Clutch 6 Eggs 5 Eggs 4 Eggs 3 Eggs 
4.5 14 4] 27 18 
49 10 71 19 0 
4.6 9 50 31 9 
48 27 A? 27 4 
4.3 0 43 43 13 
ng ce ee ee er ee ew re ee 
19 
