Beaver Lodge - a photo on Flickriver

Beaver Lodge

            The American beaver (Castor canadensis) is a large aquatic rodent that ranges across much of North America.  Trapped and persecuted in Massachusetts to extirpation by the turn of the century, the beaver was reintroduced to the Commonwealth in the 1950's, beginning in a remote section of the Quabbin Reservoir.

Highly ambitious and adaptable, the beaver quickly dispersed and reclaimed much its former Massachusetts habitat.

Though much maligned for occasionally disrupting our own suburban ambitions, the beaver's return to the state coincides with the rebound of several other species dependent upon the cyclical wetlands and meadows resulting from the beaver's work.  One of the most striking cases of this is the resurgence of the great blue heron, whose population decline in Massachusetts was a great cause for concern in the 1970's and '80's.  With the absence of standing deadwood surrounded by water for the herons to build their platform nests, the great blue heron became an unusual breeder in the state.  Great blue herons, however, are once again fairly common breeders in Massachusetts due to the impounded waters of beaver dams.  The comeback of the wood duck and increase of the hooded merganser are two other good examples.

The landscape cycle initiated by the beaver is a classic example of the pulsing habitat availability to which most early successional breeding birds have adapted.  Beavers often initiate dam building in situations where there is a wide basin of dense shrub growth and/or a canopy of hardwoods.  They build dams to allow them to swim to their food (bark).  As impounded waters rise, much of the inundated vegetation dies from flooding, creating a wealth of nesting opportunities for such species as tree swallows, eastern bluebirds, northern flickers, great-crested flycatchers, brown creepers and great blue herons.  Soon after, the standing deadwood will support large numbers of insect larvae, creating a boon for woodpeckers.  On shore the beavers begin felling trees and opening shrubland as they harvest food.  The impounded water itself creates important habitat for breeding and migrating ducks, and important food sources for others like belted kingfishers, osprey and river otter.  Often the periphery of impoundments will support cattail beds that in turn support Virginia rails, and occasionally rare species like sora, pied-billed grebe, American bittern and marsh wren.

Eventually the beaver will exhaust the food supply of the impounded area, moving on to a new section of the waterway where they will build a new dam.  In their absence the old dam will eventually fail, draining the pond and creating exposed mudflats important to migrating shorebirds like the spotted sandpiper, greater yellowlegs, killdeer and solitary sandpiper.  Within a year the flats will be covered in grasses and wildflowers; a situation referred to as a Beaver Meadow.    Beaver meadows are fascinating habitats, and in pre-settlement days there is evidence that the larger beaver meadows of New England supported populations of grassland birds such as the bobolink, eastern meadowlark and savannah sparrow.

In time the beaver meadow will succeed back to a woody state, and throughout the entire process will provide critical habitat to various suites of birds.  Most prominently, the suite of early successional breeders which includes blue-winged warbler, common yellowthroat, chestnut-sided warbler, yellow warbler, willow flycatcher, eastern kingbird, gray catbird, eastern towhee and indigo bunting can be found at this stage.

As succession continues the food supply will return for the beaver, and with it, the beaver will also return, setting the whole process in motion again.

Taken in: United States / Massachusetts / Hardwick (show map)

Taken on: December 30, 2006

Tags:

beaver

american beaver

canadensis

castor canadensis

beaver dam

beaver pond

food cache

beaver lodge

beaver meadow

early succession

great blue heron

quabbin

quabbin reservoir

quabbin reservation

quabbin watershed

gate 43

gate 44

eqlt

east quabbin land trust

massachusetts

dryoptera

chris buelow « less

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Camera: Canon EOS 20D, f/20.0, 1/200 sec, 130mm, ISO 1600 (more info) (hide info)

Camera:	Canon EOS 20D
Aperture:	f/20.0
Exposure Time:	0.005 sec (1/200)
Focal Length:	130mm
ISO:	1600
Exposure Bias:	0 EV
Flash:	Off, Did not fire
Exposure Program:	Shutter speed priority AE
Exposure Mode:	Auto
Metering Mode:	Average
White Balance:	Auto
Color Space:	sRGB
Software:	Adobe Photoshop Elements 2.0
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