- 
B.S. 25971- Immature Frigate 
Bird. Johnston Island. 
July 12, 1923. 
1743. Two adult male Frigate 
birds with throat sacs fully dis- 
tended. Bird at left is mating and 
has sac full size. The bird at 
right has begun incubation and sac 
is beginning to shrink. Lays an 
Island. 
1923. 
1744. Eric Schlemraer with two adult male 
Frigate Birds with throat sacs fully distended. 
Bird at right is mating. The one at left has 
begun incubation and sac is shrinking in size. 
Lays an Island. 
May 2, 1923. 
