Friday, June 14, 2019

Nature's Waste Management

Several years ago on a hot summer day walk I came upon a young lady approaching from the opposite direction, peering at the vultures circling above with a look of fear and repulsion on her face.  She said in passing"I cannot stand those big birds".  I restrained my impulse to launch a pedantic lecture and responded that she really didn't want to live here in summer without them; they were critical to the well-being of this community.


This Turkey Vulture found something stinky in the 
rushes next to a salt marsh

True, they are no match as eye candy for Painted Buntings and Prothonotary Warblers, but they do the job keeping our warm and humid air clean enough for us to breath without gagging. The Turkey Vulture, with the bare red head and neck, is the larger of the two species, but strangely enough it feeds on small roadkill such as squirrels.  The smaller Black Vulture, the one with the white wing-tips, sometimes feeds in large flocks on the side of the road, and a gang can make quick work of something as large as a deer. 

However, the choice of foraging is related to how both species find food. Turkey Vultures have a much better developed sense of smell which may account for why they frequently find smaller carrion that Black Vultures miss. Turkey Vultures will arrive at a foraging site first, and the Blacks follow by observing the feeding behavior of early arrivals. 

The naked heads also serve a purpose. Since both birds can frequently be observed eating from the inside out (gross!), it prevents contamination of their feathers, and the potential spread of disease. In fact their very scavenger role in the ecosystem helps prevent the spread of disease to other animals as well as humans. So, while this treatise is about neither pretty bird nor pretty subject, woe unto our island without a healthy population of both species.
A sinister looking Turkey Vulture 
roosts for the night

Vultures, often incorrectly called buzzards, are widely spread across much of North and South America, and are closely related to the endangered California Condor.  In fact it wasn't too many years ago that the American Ornithological Union grouped our majestic Bald Eagles with vultures. 

They are masters of the air as they hunt for prey.  
A soaring Turkey Vulture from below
Turkey Vultures in particular are not often seen flapping their wings, but both species hunt for rising columns of warm air called thermals.  Those currents keep the birds effortlessly aloft for long periods of time while looking for the next meal.

Unlike other raptors, the hawks and eagles, vultures feet are adapted for walking.  They have no sharp talons and depend entirely on the bill to tear into their prey. 
Interestingly, in  spite of their homeliness the Turkey vulture's scientific name Cathartes aura is often interpreted as 'purifying breeze'.  Indeed.




A Black Vulture with its exposed head and neck.  You can listen to the Black Vulture's lovely song right here.



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