Why so many vultures?

Coasting down the hill on my bike, I turn my head and there it is, a dark angelic form, big as an eagle, soaring just off my left shoulder. We cruise together for a spell, then the bird banks away, the low sun laying a rosy tint on its black feathers. Ahead, hundreds circle low, turning the sky into a swimming confusion of slicing dark lines.

As dusk approaches, the vultures gather in tall pines and oaks around Sewanee’s downtown, clumping by the dozen on high branches. They settle slowly, restlessly hissing at new arrivals and flailing their huge wings at neighbors. With a start, the whole group startles into wheeling flight, then returns to roost with flustering feathers.

vulturesafterwetcoldnight

This roost formed last year in early winter, grew into a gathering of two to three hundred birds, then dissolved as spring wore on. This winter they are back. The talk in town often drifts their way. Why so many? Are they drawn to some hidden bounty of dead animals? Might a leaking gas pipeline be luring them? What danger do they pose?

I suspect that several factors have converged to bring us this spectacular daily display. One of these causes is the regional increase in vulture abundance. DDT’s effects are no longer felt by these birds, fewer people shoot them, and as deer and small mammal populations have increased, the vultures’ food has become more plentiful.

Wintertime abundance of Turkey and Black vultures. I constructed this graph from the Christmas Bird Count data from Alabama, Tennessee, Georgia, and South Carolina.

Wintertime abundance of Turkey and Black vultures. I constructed this graph from Christmas Bird Count data from Alabama, Tennessee, Georgia, and South Carolina. The graph shows populations since 1970.

In addition to this long-term trend, the record-breaking warmth of the last two winters also likely contributes to the recent increase in vultures in our area. Birds that previously would have flown to Florida or Mexico may have curtailed their migration. Why wing to Veracruz when you can dine on ‘possum and venison in a relatively balmy Tennessee or Georgia?

Local changes also play a role. Until last winter, the vultures were roosting here, but mostly out of sight in the valleys and mountain slopes. Why the move? We cannot know for sure, but it may be that these vultures have discovered that no-one harasses or shoots them here in town. It may also be slightly warmer. Like some other native animals, they have found that lingering near human habitation may bring benefits.

The vultures in town are gathering to sleep, not to feed. On all but the most dismal days they disperse every morning, surveying the surrounding countryside for food. They return to sleep in the safety of a group. Certainly any dead animal near the roost gets eaten promptly (a dead deer on the highway near town was snarfed within a couple of days), but feeding is not the purpose of this gathering. Nor can gas leaks explain the behavior. The birds are congregating away from the gas pipeline and show no attraction to any of the gas pumping stations in town.

Do the birds present a danger to humans or pets? My research indicates that dangers are few. If the roosts get larger and persist for many years, their fecal matter might accumulate and start to smell. These droppings are no more threatening than those of other birds; indeed vultures’ powerful guts probably kill more bacteria than the guts of other bird species. Temporary winter roosts present less of a problem in this regard than permanent roosts located further south (where some vultures have, in addition to depositing guano, turned into vandals). Another threat is unlikely, but memorable: vultures defend themselves by vomiting on their assailants, so it is possible that foolhardy hazers of the roost might get an unpleasant (and potentially bacteria-laden) shower. This outcome can be avoided with some common sense. Don’t climb roost trees. And remember the ornithologists’ Golden Rule: keep your mouth shut when you look up.

vulture

Of all the species that I researched for The Forest Unseen, vultures were perhaps the one that most changed my everyday experience. I see them many times each day, yet until I knew just how fabulous they are at purging the land of dead animals, my appreciation for their lives was far too limited. No other animal removes carrion with such unassuming efficacy. A vulture gut will kill anthrax and other bacteria, a feat that no other scavenger can match. The near extinction of vultures in India has underscored their importance. As vultures declined, the populations of other scavengers surged, leading to a plague of feral dogs and rabies (and problems for people who use vultures for funerary purposes).

Being followed on my bike by a death-eating scavenger was, therefore, an unexpected delight. The dark forms that soar overhead or sit hunched in tall oak trees are to be admired. Their easy, loping wingbeats are beautiful memento mori, sky burials for the thousands of animals that live and die on this mountain. Like living prayer flags, their presence delivers a very real ecological blessing on the land below.

vulturerow

23 thoughts on “Why so many vultures?

  1. Robley Hood

    David, last year I went again and again to their roost on Florida Avenue, and this year I have watched them gather not far from your home. I love the way they congregate, first soaring in the sky, each afternoon. I have started thinking of them as gossips gathered on bare limbs to share tidbits about their day’s adventures. These are spectacular creatures for which I am grateful. Thanks for this post!

    Reply
  2. C.C.

    Thank you for sharing this bounty of info on a bird that also roosts in my neighborhood a lot (north Albuquerque along east bank of Rio Grande in our bosque). It is great to be able to understand a bit more about why they suddenly are around sometimes, and at other times gone. So many factors presented here – benefits of city, warmer temps influencing migration. I have always reveled in their large numbers – their “kettles.” I, too, have known of their cast iron gut and their service to our world with carrion. And I chuckled that you used a family favorite word – snarf. In my reality of abundant food, I find myself concerned for wild among us, that they are getting enough in this drying-out, human-encroaching land.

    Reply
    1. David George Haskell Post author

      Thank you! Snarf is a favorite word and activity.

      So far, vultures seem to be weathering the changes that humans are bringing to North America. DDT knocked them back but they are certainly coming back. Hopefully this continues.

      Their cousin the condor is not doing so well: habitat changes and lead ingestion are major challenges for these birds.

      Reply
      1. lbrasher

        My grandfather told a story about a someone who took a local fellow (from Sewanee, no doubt) to see the view from the cliffs on the top of Lookout Mountain above Chattanooga. He stepped back to let the man take in the full grandeur of the scene. When he reapproached, the viewer said, “I’ve seen somethin’ today I never saw before–the back of a buzzard, and him a’flyin.”

        Reply
  3. manayunkia

    It reminds me of the dung beetles, who, like buzzards, have an unappreciated role as ecological janitors. Though dung beetles are not the eaters of the dead like the buzzards, they do take on a task many of us find disgusting. They, too, are quite efficient in their task and we humans owe them a thanks because if all that cow poop stayed in the pasture and not balled up and rolled away and buried to produce more baby beetles, we’d have a huge flying pest problem. Just ask Australia who introduced cow (and cow patties) not recognized as a food/brood source by native beetles and as a result had many patties and many, many flies that did recognize the patties as a food/brood source! The solution? Introduce non-native dung beetles to break down the patties. Nothing like a little ecological re-engineering of a continent that began with dumping a few prisoners on an island long ago.

    Great post.

    Reply
    1. David George Haskell Post author

      Thanks David. Glad you liked the post. The dung beetle parallel is a good one. A coda to the story: overuse of ivermectin on cattle apparently wiped out the dung beetles in many ag areas in the US, to the detriment of nutrient cycling. I also wonder whether ivermec might affect larval fireflies — some fields here have lots, others none, and I wonder why. Maybe I’m ivermec paranoid (despite having felt its benefits myself, a story that will wait for another day…)

      Reply
  4. Mark E. Davies

    “raptor biologist” sounds way cooler than regular biologist

    convergent evolution, vultures Old v. New, displayed/explained via the just published ‘Unfeathered Bird’ – http://ow.ly/i24Ap

    “The vultures prefer suburban or urban to rural, both for volume of available dead animals to eat, and for the reduced likelihood of taking a shotgun blast in the tail feathers.” http://ow.ly/i254r
    Hopefully no ‘bangers and screamers’ (yet?) in your town.

    Reply
  5. iNaturalist.com (@inaturalistcom)

    It’s great to read more about these birds! I have found them to be increasingly bold, and if I sit down near some black vultures, they will approach on foot… not necessarily what I want! Hard to imagine that people have been giving them handouts… Perhaps I appear to be in my final hours!

    Reply
  6. flatland57

    Great post! Who knew about funerary purposes? Not me. Here in central Maryland we have a large group of vultures that roost near the Baltimore County dump, north of the city. They’ve been there for years. Sometimes there will be as many as fifty of them, circling overhead. You can also find them congregating along interstate I-83, near the dump, in big groups, standing alongside the highway, and on median strips. They’re fearless.

    I live in the city and we now have our own local set. Not nearly as big a group, but definitely a group. I was thinking that their habitat had been disturbed, but the advantages of living near a dump are obvious, just as they’ve taken up residence here in the city in a big park that also sits conveniently along a major road.

    There has been an ad running that has a Big Year storyline. Two guys are seen arriving in secluded spots with cameras at the ready, each hoping to be the first to get a glimpse & picture of some exotic bird. When the bird finally appears, it’s a vulture. Too funny. They’re everywhere.

    Reply
    1. David George Haskell Post author

      It is surprising that more cultures have not made use of vultures for corpses. I guess as long as there is deep soil, burial is the guaranteed way to control any possible diseases, etc.

      Glad to hear about your local crew!

      Reply
  7. kareningreensboro

    I’ve not seen a roost here in Piedmont North Carolina, but a couple of years ago while driving a back road from Greensboro to Chapel Hill, I came upon a huge flock of black vultures (probably 50-60) feasting on a fish kill in a large pond at a dairy farm. My guess the fish kill was due to large amounts of either fertilizer or cow dung and the extremely hot weather we were experiencing at the time.

    I pulled off the road to take pictures and to marvel at how many there were at one time (I had only seen them in smaller groups of two or three). By the time I returned on my way back home to Greensboro, they had all gone along with most of the fish kill. Effective scavangers, indeed!

    Karen

    Reply
  8. Annie McGarry

    Wonderful post, David. My new neighborhood in Pittsboro, NC is home to over 70 turkey vultures. I’m 12-30 miles from Greensboro and Chapel Hill, so is it possible the earlier commenter saw my neighbors eating the all those fish? I’d wondered how such a large group gets by, and assumed they must cover a large territory. Meanwhile, an opposum carcass continues to decompose next to a nearby busy street. Do dead animals get too rotten to be attractive? I would imagine so, but that’s me.

    Vultures have morbid and revolting associations for most people, but a local man redefined vulture-phobia for me. He saw a vulture land on one of the trees near his house, and he cut the tree down. I asked why, and he looked at me like I was simple and said, “They stand around in dead stuff.” I told him why I like them, including that they will eat my dog only if he’s already dead (I didn’t know black vultures would take down livestock.) He now regards me as more peculiar than he initially thought, but he seems to get a kick out of me. He may even be more fond of vultures.

    I once lived near a murder of crows, and as much as I respect them, I truly appreciate the relative quiet of the t. vultures. Watching them soar and settle has become a favorite ritual here. And you can be sure I am going to keep my mouth shut when looking up from here on out. Thanks for answering some of my questions.

    Reply
    1. David George Haskell Post author

      Annie,

      Thank you for these great stories. And thank you for putting in a good word for the vultures with your neighbors. Cutting down a tree to get rid of a vulture is quite funny really, but not for the tree of course. Sounds like the start of a fable.

      Vultures do have preferences: they do not like animals that are too putrid. They also (depending on how acclimated to humans they are) prefer to eat away from disturbance. So of the ‘possum was in a place with lots of cars, dogs or people, the vultures may have left it even if it was still “good.”

      Crows are spectacular in their own way and, as you know, silence is not their strong point. They remind me of humans in that regard, always chattering and yelling.

      Best wishes, David

      Reply
  9. Pingback: Gratitude | Uncivilized Animals

  10. mefurr

    I thought I’d already liked this post, but was reminded of it today when a fellow blogger posted about vultures and other wildlife in her backyard in New Jersey. I was treated recently to the sight of upwards of 120 black vultures roosting together in Manatee Springs, FL. Quite a sight! I’m mulling over my own tribute to these amazing birds, who are unjustly reviled by so many (along with the opossum, which I think will be the topic of my next post once I get settled in my new job and find the time!) Will be sharing this post with my friend. Wonderful!

    Reply
    1. David George Haskell Post author

      Thank you! We’re being treated to flights of hundreds in the evening at the moment. Beautiful. They slapping sound of their wings in the branches can be quite loud.

      Congratulations on the new position!

      Reply
  11. Tim

    Great article! We are seeing the same thing in late February as for north as Youngstown, Ohio. 50-100 at a time. In southern Ohio where my daughter attends college at Ohio Univ n Athens, they have thousands. They have black and turkey. I believe we just have turkey vultures. They are fun to watch. But my wife thinks they are creepy. Good to know their defense against assailants! I took some pictures directly below the tree they were roosting in. I was lucky!

    Reply
  12. Randi Borel

    many years ago, before cellular phone with photo capability, best guess….in the past decade…. I encountered a group of hundreds of turkey vultures assembled in winter trees pines and other types trees, as though they were waiting for something. I searched back then on line and never was able to find anything about these gatherings though I was searching for vultures not turkey vultures. Actually when walking in the woods with my dogs I have seen turkey buzzards quite frequently. they roam this area…I am located in lower appalachian mountains in a county in north east georgia. This location gathering, was in a rural area on usa forest lands along side a road which i walk dogs off leash. All this land perhaps may at one time have belonged to the Cherokee nation. It is only today I read on a blog that turkey buzzards gatherings and in flight over lands offer to the land… earth… purification. I thank you for the posting and all other who have commented. It could be enlightening to contact someone in Cherokee Nation to learn more about these gathering and the reason and what it may mean for our planet and area. I find there is also plenty online about turkey buard totem and shamanism…

    Reply

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