Archive for the ‘ornithology’ Category

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A Time For Turkey Vultures

September 3, 2010

In the same vein as last week’s offering, I’d like to expound stream-of-consciousness-style on the topic of Turkey Vultures.

Tomorrow, September 4th, is the Tour De Fat (TDF) in Fort Collins, an increasingly popular bike parade put on by the increasingly popular New Belgium Brewery. In it virtually all the riders wear costumes or other unusual adornments, thereby making it a spectacle to behold. Now, it also happens to be International Vulture Awareness Day (IVAD), which is a very recent addition to the calendar initially created a couple years ago for the preservation of threatened Old World Vulturine birds. The stars were thus aligned, and all I needed was a reason to conjoin these two disparate occasions.

I learned of an outrage in Sterling Colorado last July, where some cowardly stain on the human race decided to shoot Turkey Vultures there on three successive days and thus have three individuals sent to the Rocky Mountain Raptor Program (RMRP) to remove the shot and undergo chelation treatment to ease the lead poisoning. Maybe I was in a vulnerable moment – I have a lot of those lately it seems – but because of my interest in conservation and humane treatment of animal life, I am put on edge when I hear stories like the above, and something in me then clicked when I learned of the congruence of IVAD and TDF. Like the cosmic pas de deux of a solar eclipse, I realized that this was an opportunity to both participate in TDF as I had always wanted, and to do so serving a higher purpose – communicating the greatness of birds and in this specific case, Turkey Vultures. TuVus lack a syrinx and therefore are unable to speak for themselves in Northern Colorado – but you can bet your ass that I’ll be there to speak up for them tomorrow, in front of thousands of people in a way no one has ever seen before. I will be dressed up as a Turkey Vulture and ride in the parade along with 3 other similarly-bedecked companions, spreading the good word about TuVus as we make sure that at least in Fort Collins, these birds will continue to have a safe place to roost and forage every year.

So what is it with me and Turkey Vultures? When I first brought up my desire to participate in the TDF at a rounds meeting several weeks ago, I think people got the impression that I was a longstanding vulture afficionado, and that like some people I know, they were really my “thing”. It’s reasonable to think that, although I wouldn’t characterize myself that way, especially now that I know several people who in my estimation are true full-on, hardcore vulture-philes.

For me, my interest and appreciation of vultures stems largely from a couple personal relationships I have with vulture individuals, namely the “Old Male” and “New Male” educational Turkey Vultures at the RMRP. I’ve been a handler for the Old Male for over 5 years now, and the New Male for 3 or 4 (I’ve lost count). Before I handled either of these birds I used to think of Turkey Vultures as rather ugly creatures, much in the same way that the people I greet in public when I am handling will often tell me outright. I’d have thus agreed with them 5 years ago, but now when I hear those words, like say, “My god what an ugly bird!” I actually react in a bit of shock and revulsion. It crosses my mind that if I didn’t have that vulture in my care at that moment, I just might pop that knucklehead, be it man or woman, right in the jaw for saying that, as if they’d addressed that sentiment to a child of mine. Of course, in actuality I show much more restraint than that and merely offer a polite verbal counter to that suggestion. But now you know what I’m really thinking when I am responding so diplomatically.

So what changed between 5 years ago and now? Maybe it was just getting to know these birds not just as representatives of their species, but as individuals with distinct personality (or  bird-onality?) traits. I can assure you that these birds are distinct from one another, and that even if their feet were obscured from view (the Old Male is missing a couple toes from an ancient bout with frostbite) I could tell them apart from a distance based on just their posture and body language. Over time I watched them closely, and noticed them noticing me in kind. I can’t say what it is they notice or remember about me from one time to the next, but the way they cooperate with me, respond to my voice and actions, and offer me those charmingly quizzical looks, suggests to me that their vulture minds are just as active and curious as my human one. I find myself simultaneously enchanted with both the things I know intellectually, abstractly about TuVus in general, and with these particular birds with their droll characters. Whatever ugliness they have has become invisible to me. The smell of their barf, well, that’s another matter, but in no way do I see anything hideous in these creatures anymore.

Turkey Vulture, in Key West, Florida, 16 December 2005.

A few taxonomic and natural history notes: Turkey Vultures (Cathartes aura) are members of the rather small avian family known as Cathartidae. This strictly New World family also includes the Black Vulture (Coragyps atratus), commonly seen in the southeastern US and in southern Arizona, as well as the condors, the endangered California Condor (Gymnogyps californianus) and the South American specialty Andean Condor (Vultur gryphus). There is also the King Vulture (Sarcoramphus papa), a strikingly plumaged and strictly tropical species, and two other less well-known close cousins of the Turkey Vulture, the Greater and Lesser Yellow-headed Vultures (Cathartes melambrotus and Cathartes burrovianus respectively). Greater and Lesser Yellow-heads are in fact so similar to Turkey Vultures structurally that you really need to get a decent close-up view of their heads in order to tell the difference. You will only find the Yellow-heads in the tropics and subtropics however. For example, I had the pleasure of seeing a number of Greater Yellow-heads in the Manu Biosphere Reserve in Peru back in 2005.

All the Cathartes vultures possess extraordinary olfactory powers, and experiments have shown them capable of locating hidden carrion from miles away. The other vultures are not thought to have as much ability in this department, and instead probably rely more on visual location or just looking for where the Turkey and Yellow-headed Vultures are going to find food.

On a naming note, local naturalist Kevin Cook has said the Cathartids should commonly be referred to collectively just as “condors,” to distinguish them from the Old World Vultures. Confusingly, the birds we call “vultures” here in the states include both the Cathartids and the Old World Vultures, with the latter being closely related to hawks and eagles and are thus Accipitrids. In the Old World, Accipitrids are sometimes referred to in the common vernacular as “buzzards”, which here in the US is a term applied to, yes, vultures. Clear as mud, yes?

But anyway, back to Turkey Vultures and Tour De Fat. I hope to have some photos to post in the coming days of my costume and participation in what I’ve christened Tour De Vulture. I don’t know if this will be an annual phenomenon, although I hope it will. During my travels next year, I hope to photograph all the aforementioned Cathartids, and help further the enlightenment of the world about these essential and fascinating birds.

The Old Male Turkey Vulture and me at a recent exhibit in Fort Collins

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The Cornell course: unleashing the inner nerd

January 31, 2010

After three years of hemming and hawing over whether I would get something out of it, I finally caved and decided to enroll in the Cornell Lab of Ornithology’s home study course. This is the course where you basically read the entire Handbook of Bird Biology, cover to cover, and take open-book written exams on it after each chapter and send them in to be graded and discussed by the course staff. You can take the course as fast or as slowly as you like, and when you’re finished they’ll send you a certificate of completion. There’s no automatic college credit given for completion, although with some finagling and persuasive argument you may be able to bargain some credit from an institution.

The Handbook of Bird Biology is big textbook. The creators seemed to know that, and to make the book slightly less intimidating they don’t even number the pages in typical fashion. The pages are numbered separately in each chapter, so the reader can’t just thumb to the back and say “Good grief, this book is a thousand pages!” or whatever it is. Subtle, but oddly effective.

The book is also quite expensive. To enroll in the course with the book is about $300, but if you already have your own copy it’s only $200. The book retails for a little over a $100, but I’ve borrowed mine from the CSU library for 3 years now, and I just renew it electronically every month. No one else at CSU seems to want to check it out, so this system works for me.

Bridled Titmouse (Baeolophus wollweberi)

Bridled Titmouse (Baeolophus wollweberi), Madera Canyon, Arizona © 2008 Eric DeFonso

I’m also “augmenting” my taking of the course by creating my own syllabus where I do supplementary reads to the chapters in the Handbook, in other ornithology text books or on web sites. I’m an information packrat, and I have the Gill as well as the Proctor & Lynch textbooks on ornithology, and I’ve planned out which chapters to read in those books along with the chapters in the Handbook to improve my contextual understanding of the topics covered. Another highly detailed resource I’ll be using is the Ritchisong ornithology syllabus from Eastern Kentucky University. I’ve found that I learn things really well this way, when I can see the same information but presented in different ways or formats. I think it’s called synthesis. It makes for more work for me I suppose, but my goal is to learn the stuff in and out, and well, if this is what it takes for me to get the most out of it, that’s what I’ll do. It’s fun for me anyway, so I don’t really mind.

So what changed my mind to make me want to take this course in the first place? Well, you may have read about my recent decision to take the Macaulay Library Workshop on Recording this June, from an earlier post. This decision is obviously related to that. I’m really going to take the plunge, and I mean plunge headlong into ornithology. I have another announcement in the coming weeks about things I’m going to do soon that will really put all this into perspective.

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Lark Buntings

January 13, 2006

Tonight’s guest speaker at the monthly Fort Collins Audubon meeting was Amy Yackel Adams who spoke about her CSU dissertation work on Lark Buntings and their population status at the Pawnee National Grasslands. It was a very nice talk in front of an attentive and good-sized crowd. Some take-away points:

  • The Pawnee Grasslands (PNG) are home to the highest breeding concentrations of Lark Buntings (LABU). She says the birds are generally very prompt in arriving on May 1 in spring migration. The males show up about 2 weeks before the females.
  • It’s been estimated that LABU populations overall are declining at about 2.1%/year in recent years, which is quite high.
  • LABU juvenile survival rates are about 20-30%, which is pretty low by passerine standards.
  • These low rates are attributable in part to their being ground nesters, and are subject to significant predation, ranging from 13-Lined Ground Squirrels to weasels to raptors. Someone did ask during the Q&A whether chemical contamination may play a part, but Amy couldn’t point to any studies that have been done on this. Her anecdotal evidence did suggest some possibility of that, based on failed nests with fragile eggshells, but nothing conclusive.
  • LABU practices “brood division” during the raising of the young. That is, say, in a nest with 4 fledglings, the male and female with each take two “under their wing” and sequester them separately in different locations, for feeding, etc. Apparently only a couple dozen North American species are known to do this, although this may be because other species haven’t been followed and studied to the extent that LABUs were in her work.
  • Neighbor Nick asked her what she would recommend as the one single thing that could be done from a conservation standpoint in order to improve the chances of reproductive success for LABU at PNG. She suggested something along the lines of reducing habitat fragmentation, which is a very big problem at PNG. In the case of PNG, this fragmentation reduces the ability of coyotes (which get hunted off) to control their usual prey, the ground squirrels – and thus the LABU end up with more predators of their own.

Of course, there was more, but it’s getting late and I want to get this off before heading to bed. Bravo FCAS for yet another great presentation!

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Cool Birds 2: the Great Horned Owl

December 10, 2005

We are blessed here in North America with one of the most fearsome as well as evocative birds – the Great Horned Owl. It is a familiar bird to most people, and yet probably only few have ever had the opportunity to witness them in closer quarters. They are by no means rare, but they are rarely seen or heard by the population at large – in most cases you do have to go looking for them to see them, often at night. The good part is that when you do see them, you will be enchanted by those huge forward-facing yellow eyes staring at you. And even if you don’t see them, just hearing their hoots, especially if you’re camping in the woods and you wake up to hear them at 4am as I have, can be just as exciting. There’s something inexpressibly haunting about knowing there are highly skilled hunters prowling the tree canopy in the dead of night.

The Great Horned Owl belongs to the Family Strigidae, the “typical owls”. This is a fairly large family, consisting of over 160 species worldwide, of which 18 live in North America. The Great Horned is not actually the largest North American owl (Snowy and Great Gray Owls are larger), but it is pretty large as owls go. They are most familiar for their resonant low-pitched hoot calls, which are what most people imagine owl calls to be – usually, two rapid hoots, followed by 2-4 slower hoots. They are nocturnal hunters, preferring to feed mostly on small mammals like rodents ands rabbits; passerine birds and sometimes game birds like quail or pheasant; and other small critters like lizards or scorpions. However, they are also capable of taking down even larger prey like skunks – at the RMRP we recently admitted a GHOW that anyone with a sense of smell would know had just been feeding on one. Great Horneds will also prey upon other birds of prey, especially their nestlings. I’ll discuss shortly how they manage to do that effectively.

Great Horned Owl, Oct 16 2005First, a couple images I’ve captured. Last September I snapped this shot of a GHOW at Cottonwood Hollow, just off Prospect Rd in Fort Collins near the Poudre River. It was kind enough to light onto a branch only yards from the trail, but as you can see it gave me the evil eye as I edged gingerly toward it for a closer look. Even though they are largely nocturnal, Great Horneds can be active during the day too, as this one was. One possibility is that this one was looking for a new nest site. GHOWs don’t build their own nests, but rather seek abandoned ones belonging to other large birds. They can also nest in tree cavities, crevices, or stumps.

Great Horned Owl with 4 chicks, April 17, 2005Speaking of nest sites – earlier in April while on a trip with the RMRP, I got this unfortunately blurry shot of a nesting GHOW in Frank State Wildlife Area, east of Fort Collins. Not easy to see, but there are 4 nestlings being watched over – an unusually high number for the species, which normally raise no more than 3 at a time. Our trip leaders remarked that this wasn’t the only fruitful nest they’d seen recently. Apparently last spring was a good one for Great Horneds here.

The definitive outward physical feature of GHOWs is their ear tufts, often called horns, but technically referred to as plumicorns. They are the source of this bird’s common English name, but these tufts are not actually associated with its ears. Owl ears are located on the sides of their heads, asymmetrically, so that they are better able to pinpoint sound direction with utmost precision, especially at night. The tufts, on the other hand, serve as both mood communicators to other owls (they can be erected or lowered), and as “shape interruptors”, a useful adaptation that makes it harder for prey to identify them as a predatory bird. The idea here is that the “horns” make it more likely that a prey item will not recognize the body shape of the owl, if, say, it is perched nearby in low light.

One of the reasons GHOWs do as well as they do is that their nesting cycle starts considerably earlier than many other birds – some breed as early as January. Their thick plumage and diverse feeding habits allow them to overwinter in colder climes, and to survive late winter freezes. This basically gives their young, who are fledged by March or April, a head start on any other nesting birds in their area, making it all the easier to prey on them and especially their young. Their prey list includes not only small owls, but even the young of other birds of prey like Osprey or Red-tailed Hawks. This early breeding is a remarkable adaptation which helps us understand why their range is as large as it is – an expansive diet increases options especially in places where specific food sources are highly cyclical.

Another reason GHOWs do well, and one reason they are such a cool bird, is that their feathers come with an amazing feature whereby the barbs on the leading edge of the flight feathers are especially long and well-separated. This serves to reduce turbulence and therefore wing noise while in flight – a silencer, if you will. The reduction in flight noise is dramatic – while tending to GHOWs in the large flights (cages) at the RMRP, I’m stunned by how silent those that fly overhead from one high perch to the other are, even while flapping. Not only does this allow them to hear their prey more easily, it gives them an extra stealth factor while honing in on their target. This feature isn’t unique to Great Horneds – in fact it is present in many owls, and even some nightjars – but it is one that for them has evolved to perfection.

Just because a bird is familiar doesn’t mean it can’t also be a cool bird. The Great Horned Owl is a perfect example of that – we in North America should be thrilled to have them right here lurking in our own neighborhoods.


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Cool Birds 1: the Hoatzin

December 1, 2005

Welcome to the first installment of a new feature for Feather Weather, a regular series on Cool Birds. These posts highlight birds which possess outstanding traits, sometimes beautiful, sometimes scary, sometimes just outright peculiar. These birds surprise and inspire us, and help us appreciate the grand biodiversity of our planet. Our inaugural feature today will be for the very distinctive Hoatzin, a bird that some consider the strangest bird in the world.

I was fortunate enough to go on a 5-day trip to the upper Amazon basin last May, specifically to Manu National Park in Peru. Tropical South America is the only place in the world where you can find the unique Hoatzin (pronounced “waat-zin”). Hoatzin, May 19 2005, Otorongo Lake, Manu National Park, Peru This photo was taken by me on our last day in Manu, on Otorongo Lake (an oxbow lake near the river, a common place to find Hoatzin). We plied the calm lake waters in a small catamaran, and came across a half dozen individuals on a snag over the water. The other 4 left, but this character (and the one in the photo below) hung around to see what we were on about. I only had my Nikon point-n-shoot, but we got close enough for me to get this decent shot. It was a memorable moment, drifting as close as we did, all the while hearing the hiding birds perform their enigmatic wheezy whine calls.

The Hoatzin has a very primeval appearance – a blue patch of featherless facial skin, an upright spindly crest, and bright red eyes. The nestlings also possess something extremely rare among living birds – hooks at the elbow on either wing, to help them clamber back up logs or branches, in the event that they fall to the ground or into the water below. With age these hooks disappear, but their resemblance to fossilized features on Archaeopteryx adds to their prehistoric cachet.

The Hoatzin’s digestive system is also highly peculiar. Most birds have a system involving a crop, a gizzard, and the stomach – the Hoatzin’s crop instead has evolved into a foregut, making it more similar to a cow than to virtually any bird. (Only the Kakapo of New Zealand has something similar.) It needs this foregut because it digests leaves and other vegetable matter which require an area to ferment. The fermenting process takes on quite a stench though, and sure enough the bird is sometimes colloquially known as the “stinkbird”. This foregut adds considerably to the weight of the bird, making it something of a clumsy flier, which was apparent when we saw them flutter into the brush in Peru. (Fortunately we didn’t have to experience their stink!) It also means they have to spend some time digesting, which makes them relatively sedate while roosting and not so hard to see for interested birders. As to why the Hoatzin has this bizarre system, researchers remain uncertain.

The Hoatzin has also been difficult to discern taxonomically. Early systematists placed it among the Galliformes, which include birds like quail, grouse, turkeys, chickens, and pheasants. This made some sense, given the unclear relationships between these groupings of birds already – the Hoatzin was yet another mystery set among them. Hoatzin (2), May 19, 2005, Otorongo Lake, Manu National Park, Peru However, with more advanced biochemical and genetic methods, as well as continued anatomical and morphological study, the distinctiveness of the Hoatzin increased, and the closest relatives to the Hoatzin were determined to be the Cuculiformes, the Cuckoos. But including the Hoatzin among cuckoos is problematic not only because of the its aforementioned digestive system, but also unlike any cuckoo, the Hoatzin is anisodactyl, meaning that its feet have 3 toes forward and one pointing back, like many birds. All true cuckoos are zygodactyl, with 2 toes forward and two back. Thus, the Hoatzin is placed in a monotypic family (a family of one species) called Opisthocomidae. A few researchers then go further and place it in its own Order, Opisthocomiformes, while other more cautious types leave it among the Order Cuculiformes.

Regardless of whatever becomes known about the Hoatzin’s lineage, it certainly qualifies as a unique and remarkable creature. The Hoatzin is definitely a cool bird.