724 Field Museum of Natural History — Zoology, Vol. IX. 



Eggs, 2 to 6. Size, about 1.08X.82. The eggs of this and the next 

 species vary in color and size, those of the Yellow-billed Cuckoo being 

 usually pale greenish blue, somewhat lighter in color than eggs of the 

 black-billed species. Bird, tail feathers not broadly tipped with 

 white; bill mostly black. Coccyzus erythrophthalmus. 



Black-billed Cuckoo. 

 Eggs, 2 to 5. Size, about i.iSx.go. Bird, tail feathers broadly 

 tipped with white; under mandible, mostly yellow. 



Coccyzus americanus. 

 Yellow-billed Cuckoo. 



PART 4. EGGS MORE THAN 1.35 IN. LONG. 



Eggs, 3 to 6. Size, about 1.50x1.15; pale greenish blue. Nest 

 usually near water. Butorides virescens. 



Green Heron. 



Eggs, 4 to 6. Size, about 2.00 x 1.46; pale greenish blue. Nest 



near water. Nycticorax nycticorax ncevius. 



Black-crowned Night Heron. 



Eggs, 3 to 6. Size, about 2.55 to 2.70 x 1.55 to 1.65; pale blue 



or greenish blue. Nest, a mass of sticks, usually in trees near water. 



Ardea herodias. 

 Great Blue Heron. 



SECTION 2. NEST IN HOLE IN TREE, STUMP, OR POST. 



Eggs, 4 to 6. Size, about .84 x .65. Eggs sometimes almost pure 

 white, usually very pale blue or bluish white. Sialia sialis. 



Bluebird. 



SECTION 3. NEST ABOUT DWELLINGS AND BARNS. 



Eggs, 3 to 5. Size, about 1.12 x .80; color, greenish blue. 



Planesticus migratorius. 

 Robin. 



SECTION 4. NEST IN OPEN FIELDS, ON GROUND, OR 

 IN BUNCH OF GRASS. 



Eggs, 4 to 5. Size, about .80 x .60; color, very pale blue. 



Spiza americana. 

 Dickcissel. Black-throated Bunting. 



