Columbia subject headings:
Harvard subject headings:
Birds--Behavior--Tropics--Congresses.
Birds--Tropics--Behavior--Congresses.
Birds--Tropics--Congresses.
Ornithology--Tropics--Congresses.
Princeton subject headings:
Birds--Tropics--Behavior--Congresses.
Birds--Tropics--Congresses.
Ornithology--Tropics--Congresses.