During migration, birds are particularly vulnerable to predators. They're unfamiliar with their surroundings, and are tired and hungry after the long journey. At last, the first big wave of Baltimore Orioles was reported from Texas. On Saturday, ornithologists from Cornell University counted over 200 among thousands of birds that had just flown across the Gulf of Mexico. So far we haven't had an enormous surge of oriole migration.
Orioles are tropical migrants, and their migration is closely timed with daylength.
The first few Baltimore Orioles have arrived on the Texas coast, and more should be landing with the next cold front. Bullock's Orioles are already heading up the California coast.