The flats near the mouth of the Kenai River host one of the largest, if not the largest, colony of herring gulls in Alaska. At the end of the breeding season, it is not uncommon to find more than 30,000 adults and young occupying the site, with much smaller numbers of glaucous-winged gulls and Arctic terns.
Adult herring gulls arrive by the thousands on the flats each spring to build nests of mud and grass and lay clutches of one to three speckled olive or brown eggs. Both parents share the three- to four-week incubation duties, and then they take turns guarding the nest and hunting for food for their young brood.
Typically, the gulls will harvest hooligan or salmon smolt, but they scavenge fish-processing waste from area canneries and rob chicks from the nests of other bird species. The adults ingest the food and regurgitate it for the chicks to eat. Herring gull chicks grow rapidly on the rich diet available near the river mouth, and they are able to fledge in only a matter of weeks. By fall — despite the predation of bald eagles and other predators — the chicks swell the ranks of the herring gull population, which then leaves the central Kenai Peninsula and begins flying down the coast to continue feeding throughout the winter.
Most of the herring gull eggs have hatched by now, and those interested in watching the birds can observe
them readily with binoculars or a spotting scope from the bluff near the Kenai Senior Center.