By Charles Segebrecht
Vultures don’t settle into just anywhere. They are discerning where they roost. Like us, certain conditions must be met: recreation, scenery, community, safety and, of course, requisite grocery stores and restaurants. A recent influx of turkey vultures to Lake Quivira are nothing for us to fear – either for their numbers or our safety. These necessary birds are simply sharing our local amenities with us. Why live or roost anywhere else?
Perhaps they would prefer to enjoy a view aloft over Yosemite National Park or of the New York City skyline, but undoubtably prefer the food source ease and its prevalence found in the east settling pond, along Interstate 435 and at the Waste Management landfill. We witness them departing in the morning to begin their scavenging, and again as they return in the evening primarily to the taller trees on and around Treasure Island. With some of their safety derived from population numbers, their community count has recently surpassed one hundred. This also suggests lots of carrion in the neighborhood (or now lots less carrion in the neighborhood!).
Colder temperatures in the north are at play, too. Their featherless heads don’t like the cold; thus, they survive as a migratory bird. This time of year, they are slowly pushed southward into Texas and sometimes even to Mexico. When conditions are ripe, they stick around for a while and contribute as only they can, to our Halloween experience. They probably scare other birds away, but pose no actual threat to us, our pets or even small trick-or-treaters.
No one here remembers Lake Quivira becoming such an evening sanctuary for turkey vultures. Eagles, yes–when the perfect northern winter storm occurred three or four years ago driving them south But never vultures. Mike Cooper, one of our wise local birders, hypothesizes Water One was unknowingly involved. They began clearing land last month along Renner, where he has noticed vulture migrations in previous years. He suggests the demolition activity moved their typical migratory roosting to the east and into our taller trees. We’re confident, however, it has nothing to do with decay of a neighborhood.
It’s amazing how feathers make a perceptible, skin-deep difference. Imagine, if you will, feathers on a vulture’s fleshy head, and these wicked-looking birds begin to appear regally eagle-like. Our disgust and fear dissolves. The absent feathers are just part of an amazing evolution of a bird with a niche purpose of providing a necessary and positive environmental impact. They are sometimes called “nature’s clean-up crew” as their scavenging ways help prevent the spreading of diseases such as rabies, salmonella and tuberculosis.
The absent head feathers are environmentally advantageous, keeping the skin surface bacteria count down. Vultures are exposed to many scary micro-organisms in their main diet, and thus, feathers are also not found on their legs. Their strong stomach acid level evolved to meet the challenge of digesting all the organisms and compounds found in their sometimes-fragrant food –even anthrax! Their urine is also highly acidic. They urinate on their legs with this killer solution to help deal with the same bacteria they encounter, thereby solves another evolutionary trick: to keep themselves cooler in hotter climates.
Sadly, over half of the twenty-three species in the world (at least one species of vulture can be found on every continent except Australia and Antarctica) are either threatened, endangered or critically endangered as the result of human impacts.
One direct result of lessening vulture numbers: rabies has become a very real problem in India. Ninety-nine percent of the vulture population is now decimated from eating deceased cows treated with a certain medicine. The kidneys of these poisoned vultures shut down, resulting in their deaths. Dogs now flourish in growing numbers with the increased food source of deceased cows. Rabies is spreading among this expanding dog population, and humans now are threatened. It’s called stochastic planning–the ramifications of an action are not considered.
As you walk or run by the east settling pond, and as you keep an eye on the vultures circling overhead, pace yourself; don’t overdo it. Even though you don’t yet reek as carrion, they see yo.u Should you collapse, they may begin to take notice. The ability for vultures to soar above a decaying smell is partially myth. They freely float, seemingly effortlessly, because they can–all on updrafts (spotted at 37,000 feet!) while they are smelling and looking intently to find their next meal.
They primarily rely on seeing the roadkill, spotting a fallen animal or noticing other foraging animals to lead them to their next clean-up meal. Once they’ve arrived at dinner, they use projectile vomiting to scare away the other competition–up to ten feet away. An odoriferous rot is not an essential to a meal. This will surprise you: they prefer fresh meat to rotting. In fact, some species prefer a more well-rounded diet, including nuts and fish. Meal basics, as defined by studying their pellets, are sheep, mice, shrews, deer, pigs, chickens, blackbirds, snakes, turtles, shrimp, beetles, woodchucks, skunks, snails, grasshoppers, mayflies, coyotes, sea lions and more. Rotting pumpkins and cow manure can even be part of their diet.
Their sense of smell has been used by natural gas companies trying to find pipeline leaks. The companies have in the past added ethyl mercaptan (emitted by putrefying animal carcasses) to their natural gas in hopes vultures would be lured to pipeline leaks.
Songbirds they are not. If you get close enough, a simple grunt or a hiss is all you will hear because they have no syrinx as other birds. A vulture with a beautiful songbird sound would seem to be a mismatch. Something peaceful and blissful would probably be preferred, however, as you lie there on the east settling pond dam with vultures standing by at the ready (such a group of vultures is coincidentally called a “wake”). A rendition from a nightingale, a pair of doves, a common loon or even The Grateful Dead’s Birdsong would be more settling. But they are most patient. These misunderstood creatures do no harm to living creatures. They spend their entire life cleaning up dead messes. We humans certainly don’t begin to do as much with cleaning up the environment!
Mark your calendars: International Vulture Awareness Day is celebrated the first Saturday of September. Zoos, aviaries, nature preserves and bird refuges provide activities to educate us as to how interesting and valuable vultures are.
Our annual neighborhood bird count contribution to Cornell University’s Lab of Ornithology world-wide Great Backyard Bird Count census will certainly include vultures if seen (next count: February 14-17, 2020). Over the years, the annual census has defined a change in vulture migration related to global warming. These birds used to migrate north for the first half of the 20th century on average around April 20; the average for the second half is now earlier, March 22.
Hopefully, the vultures will return to Lake Quivira’s amenities next spring to more appreciative locals now able to see a bit more of nature’s beauty in their big, bald heads and five- to six-foot wingspans.
By Charles Segebrecht