Thursday, 3 May 2012

Wombat


Ecology and behaviour

Wombat scat, found near Cradle Mountain in Tasmania

Wombats have an extraordinarily slow metabolism, taking around 8 to 14 days to complete digestion, which aids their survival in arid conditions. They generally move slowly.When threatened, however, they can reach up to 40 km/h (25 mph) and maintain that speed for up to 90 seconds. Wombats defend home territories centred on their burrows, and they react aggressively to intruders. The common wombat occupies a range of up to 23 ha (57 acres), while the hairy-nosed species have much smaller ranges, of no more than 4 ha (10 acres).

Dingos and Tasmanian Devils prey on wombats. The wombat's primary defence is its toughened rear hide with most of the posterior made of cartilage. This, combined with its lack of a meaningful tail, makes it difficult for any predator that follows the wombat into its tunnel to bite and injure its target. When attacked, wombats dive into a nearby tunnel, using their rump to block a pursuing attacker. Wombats may allow an intruder to force its head over their back and then use their powerful legs to crush the skull of the predator against the roof of the tunnel, or drive it off with two-legged 'donkey' kicks.

Humans who accidentally find themselves in an affray with a wombat may find it best to scale a tree until the animal calms and leaves. Humans can receive puncture wounds from wombat claws as well as bites. Startled wombats can also charge humans and bowl them over, with the attendant risks of broken bones from the fall. One naturalist, Harry Frauca, once received a bite 2 cm (0.8 in) deep into the flesh of his leg—through a rubber boot, trousers and thick woollen socks (Underhill, 1993). A UK newspaper, The Independent reported that on 6 April 2010 a 59-year-old man from rural Victoria state was mauled by a wombat (thought to have been angered by mange) causing a number of cuts and bite marks requiring hospital treatment. He resorted to killing it with an axe.

Thursday, 8 December 2011

Lincoln's Sparrow


Adults have dark-streaked olive-brown upperparts with a light brown breast with fine streaks, a white belly, and a white throat. They have a brown cap with a grey stripe in the middle, olive-brown wings, and a narrow tail. Their face is grey with brown cheeks, a brown line through the eye, and an eye ring. They are somewhat similar in appearance to the Song Sparrow.
Their breeding habitat is wet thickets or shrubby bogs across Canada, Alaska, and the northeastern and western United States; this bird is less common in the eastern parts of its range. The nest is a well-concealed shallow open cup on the ground under vegetation.
These birds migrate to the southern United States, Mexico, and northern Central America; they are passage migrants over much of the United States, except in the west.
They forage on the ground in dense vegetation, mainly eating insects and seeds.
They are very secretive. Their song is a musical trill, but this bird is often not seen or heard even where they are common.
This bird was named by Audubon after his friend, Thomas Lincoln, of Dennysville, Maine. Lincoln shot the bird on a trip with Audubon to Nova Scotia in 1834, and Audubon named it "Tom's Finch" in his honor.