In the spring this Gull can be found in its nesting grounds in western Mexico, then come summer, flocks of them will fly north along the Pacific Coast up as far north as Southern British Columbia. They flock north at the same time as the Brown Pelicans.
Their diet consists of fish and other small marine life, occasionally they will eat insects and eggs or their birds. Forages in flight over the ocean, they dip to the surface or plunge into the water for fish.
They are not a large gull, but they are aggressive and pestering other birds to make them drop their food is one of their main ways of foraging! The reason they flock north at the same time as the Brown Pelican is because this is one of their favorite birds to steal food from! The Heermann’s Gull is often waiting to snatch fish right from the pelican’s pouch when the pelican comes up to the surface after plunging into the water for food.
The Heeermann’s Gull is a little stinker! Besides stealing the fish from the pouch of pelicans, they will harass other birds and force them to drop their catch! They are a pretty gull, but very aggressive to other birds when they want food!
It is the only North American gull that breeds south of the US, then comes north during their nonbreeding season. They head south again in December to begin the cycle again.