46 NATURE-STUDY REVIEW [15:2— Feb., 1919 



BB. Small, pensile, partially supported 



*ACADIAN FLYCATCHER 



BBB. Larger, over 2 inches deep inside 



1. Of grasses, sometimes partially supported 



ORCHARD ORIOLE 



2. Of fibers, strings, and the like 



BALTIMORE ORIOLE 



IV. IN HOLES IN TREES OR IN BIRD BOXES! 



A. Nesting in colonies purple martin 



AA. Nesting singly 



B. Drilling holes, no nest at bottom 



1. Opening about i^ inches, .downy woodpecker 



2. Opening about 1% inches, .hairy woodpecker 



3 . Opening about 2 inches 



RED-HEADED WOODPECKER 



4. Opening over 2 inches flicker 



BB. Using old woodpecker holes or natural cavities of the 



same size or bird houses with similar openings, 

 building a nest at bottom of cavity. 



I. Nest of sticks house wrex 



?. Nest entirely of grasses bluebird 



3. Nest of straws and feathers 



a. Nest cuplike, open above tree swallow 



b. Nest spherical or partially arched 



HOUSE (English) sparrow 



4. Nest of fibers, wool, and feathers 



CHICKADEE AND NUTHATCH 



5. Nest usually containing a cast snake skin 



CRESTED FLYCATCHER 



BBB. Using flicker holes or natural cavities of similar size, 

 no nest built 



SPARROW HAWK, SCREECH OWL, AND *SAW-WHET OWL 



BBBB. Using larger natural cavities 



BARRED OWL, GREAT-HORNED OWL, AND *WOOD DUCK 



V. CONTAINING STICKS OR LARGE TWIGS 



A. Bulky nests in trees, 15 to 60 inches outside diameter 

 I. Very large, 30 to 60 inches 



*FISH HAWK AND *BALD EAGLE 



