An Imperial Beach Hidden Gem and Bird of the Week, the "Least Bittern"
Dec 14, 2016 04:58PM
● Published by Paul Spear
An Imperial Beach Hidden Gem and Bird of the Week, Bryan Brillhart Photography present the “Dig IB” Bird of the Week, the "Least Bittern"
This week’s “Bird of the Week” is the Least Bittern (Ixobrychus exilis),one of the smallest herons in the world, adapted for life in dense marshes. Rather than wading in the shallows like most herons, the Least Bittern climbs about in cattails and reeds, clinging to the stems with its long toes. Its narrow body allows it to slip through dense, tangled vegetation with ease.
Because of its habitat choice, it often goes unseen except when it flies, but its cooing and clucking call notes are heard frequently at dawn and dusk and sometimes at night.This tiny bittern can measure from 28 to 36 cm (11 to 14 in) in length, and the wingspan ranges from 41 to 46 cm (16 to 18 in). Body mass is from 51 to 102 g (1.8 to 3.6 oz), with most birds between 73 and 95 g (2.6 and 3.4 oz), making this perhaps the lightest of all herons. Least Bitterns are thought to have declined in many areas because of destruction of marsh habitats. Runoff of agricultural chemicals into standing marshes is another potential problem.
Habitat is in fresh marshes, and in reedy ponds, and in areas with tall, dense vegetation standing in water. They may be found in fairly deep water, because they mostly climb in reeds rather than wading.
They search for food by clambering about in vegetation above water, and jabbing downward with its long bill to capture prey at the water's surface. They sometimes flick their wings open and shut, which may startle prey into motion. At especially good feeding sites, it may bend down reeds to build a hunting platform for itself.
Their diet is mostly fish and insects. They eat mostly small fish (such as minnows, sunfishes
, and perch) and large insects (dragonflies and others); also crayfish, leeches, frogs, tadpoles, small snakes, and other items.
Nests are usually widely scattered in marshes, but sometimes in loose colonies. In one South Carolina study, Least Bitterns often nested in close association with Boat-tailed Grackles. Nest sites are well concealed in tall marsh growth. Nests, built mostly by males, are a platform created by bending down marsh vegetation, and adding sticks and grass on top.
After mating, females lay 4-5, sometimes 2-7, pale green or blue eggs. Incubation is by both sexes for 17-20 days. Both parents feed their young by regurgitation. In response to predators near their nest, adult birds may make itself look larger by fluffing out its feathers and partially spreading its wings. Legs and feet of young develop quickly, and young may leave the nest as early as 6 days after hatching if disturbed, but ordinarily they remain in their nest for about 2 weeks, and near their nest for another week or more. There are generally 1 or 2 broods per year.
I was lucky enough to spot a single Least Bittern at the lower end of the River Mouth Loop trail feeding in low tide. This is the first time I have seen this bird there, and I was happy to have the opportunity to film it. You never know what you will see in our great Tijuana Estuary. Until next week, happy birding!
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