This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is Franklin’s gull.
Because members of the gull family of birds are commonly called seagulls, it may seem odd to spot one so far from the ocean. In reality, many gull species travel far from the ocean to breed on freshwater marshes and lakes, and this is one of them. Most often spotted during spring migration walking the shoreline with other gulls at Windsurf Beach in Navajo State Park, this gull has also been found stopping to rest on local lakes and even on the golf course.
Determining the species of a gull, many of which appear similar, can be a complicated endeavor. In spring breeding plumage, the black head and bold white crescents outlining the eyes of Franklin’s gulls, along with considerations of range, narrows the field. Their upperparts are dark gray, and bill and legs reddish.
The Franklin’s gull is another long-distance migrant, wintering along the coasts of Chile and Peru. There they forage in salt water along the coastlines and as far as 30 miles out to sea. Northern migration starts in February, when they begin their long flights from South America. They travel through Mexico and up the middle of the United States to nest in the prairie pothole regions of northern states and in the midsection of Canada.
North Dakota, where peak breeding season lasts from late May to mid-July, typically hosts several large breeding sites. Thousands of pairs may nest in close proximity in noisy colonies. Pairs build floating nests in areas of open water interspersed with vegetation. Decaying nest material must continually be replaced to prevent the nest from sinking, and stealing material from a neighbor’s unguarded nest is common practice.
Franklin’s gulls are flexible and opportunistic in their feeding habits. On land they eat mostly insects and earthworms, and in water add a small amount of vegetation and small fish to their diet. They will forage in agricultural areas, pastures, wetlands, sewage ponds, lakes, estuaries and landfills. Since they eat insects that are agricultural pests, they are considered beneficial to humans.
This year the focus of World Migratory Bird Day, celebrated on May 11, is the importance of insects to the survival of birds worldwide.
For information on events, visit www.weminucheaudubon.org and www.facebook.com/weminucheaudubon/.
Photo courtesy Byron Greco