I’m probably being very foolish asking this question around April 1, but the mystery intrigues me.
Before I left LA Bay to head out to Isla Angel de la Guarda I walked up and down the beach and saw vultures everywhere, especially gathering around
any cleaned fish left on shore or hanging out on the cardóns above areas of freshly deposited trash.
But out on the big island, in two months, in an apparently very similar desert/coastal ecosystem, I didn’t see a single vulture. Not one! But I did
see ravens… lots and lots of very bold ravens, usually waiting for me to go hiking or kayaking so they could begin freely beaking around my campsite.
And several times I observed them engaged in aerial combat with nesting ospreys
Anyway, there are not many places in Baja where you won’t see a vulture in two months. In my new book I took a wild guess as to why this might be so,
but I’d appreciate any insight or suggestions… or if anyone knows of any research.
Thanks,
GrahamSkipjack Joe - 3-31-2008 at 10:53 PM
Tell us your hypothesis and we'll tell you what we think.Graham - 3-31-2008 at 11:02 PM
I was convinced it was vampires. What do you think?
GrahamSharksbaja - 3-31-2008 at 11:19 PM
Ok Skip!
Vampiros?? No way, really? I thought they were a mainland Mexico animal. Do they hang around Baja?
My thinking is that of unavailable dead animals or rather , "available food". You say there are many ravens.
Perhaps the ravans are the dominate feeders on an otherwise isolated rock. Perhaps the lack of dead animals can be attributed to the lack of
scavengers, maybe also due to the fact that the island is mostly off-limits to
the general public. Drug runners rarely clean fish ya know.
There is that annual vulture get-together down near Loreto. We've seen them all down there. It's possible the locals were off the island during
"Semana Pajaro"Graham - 3-31-2008 at 11:25 PM
Vultures at LA Bay. At least a dozen here... maybe 13.Graham - 3-31-2008 at 11:27 PM
Whoops. Picture didn't post. Believe me there are a dozen on these cardons near La Gringa.Graham - 3-31-2008 at 11:39 PM
Let me see if I can get a photograph of one of these creepy Guardian Angel vampires to upload.
If this doesn't work, I'll try again tomorrow.
GrahamSharksbaja - 3-31-2008 at 11:44 PM
Graham, I'm curious. Why would vultures fear the nocturnal bat? Do they prey on them?
Still curious, but alas, I have jury duty manana. I'll check on this post later.
[Edited on 4-1-2008 by Sharksbaja]Graham - 3-31-2008 at 11:56 PM
Found this one reposed in its coffin after a busy night imbibing body fluids.
If this fanged beast doesn't post... then I'll definitely return to this tomorrow with a brain full of corpuscles...
Graham
Iflyfish - 4-1-2008 at 01:29 AM
Be glad, really glad that they are not circling around you! Sometimes it is good not to see those things.
IflyfishMexitron - 4-1-2008 at 04:35 AM
Maybe a lack of water on La Guardia...?
Maybe because there are no roads..?
Pompano - 4-1-2008 at 04:48 AM
Taco de Baja - 4-1-2008 at 07:15 AM
Maybe the thermals aren't as good on the island for cruising around looking for grub......?Osprey - 4-1-2008 at 07:44 AM
Keeping My Cool
They're big, black, ugly and they're up there every day. Zopilotes, Turkey Vultures. Also called Buzzards they are almost three feet long, six feet
of broad black wings, weigh about four pounds. As I lie comfortably in a lounge chair, Bloody Mary in hand, composing articles and stories for
magazines and the press, I can enjoy them, just overhead. I have always admired the birds, envied their aerial elegance, the exquisite freedom flight
accords them, a freedom I can never know. From time to time I have used the birds to color my stories about this part of Mexico. So far my
descriptions of the birds in flight have been impossibly bland, add little to the stories -- "the big, black birds wheeling, gliding on the thermals,
etc.,etc.....". Better to leave them out than to paint such a colorless scene. Fellow writers have failed to capture the majesty of the creatures
--"they wheel, soar, glide -- hover, hang like big kites...ya da, ya da, ya da...." I need to really watch them awhile; get to know them, pay
attention, find the words that may bring them to life, paint them against the sky with the same grandeur we lavish on the their cousins, the eagles.
If I tilt my lounge chair back a little I can watch them without moving a muscle. Today several birds are aloft just above my patio, the wind is
strong and gusty; a good day for observation. Now that I pay the proper attention I can see why the words fail. They are not just soaring, wheeling;
they are in constant motion. This wind is not a steady flow of cool air rushing from the beach, up this little bluff to my house. It is not a stream
of air, rather, it is great puffs; pulsing, softly now, a powerful gust, soft again, little short bursts, more gusts, a shoulder against an invisible
door. The birds are not possessed of a special kind of vision, some precognitive way to see the wind, anticipate the wind's wild vacillations,
changes taking place in tiny parts of seconds; all the birds' moves are adjustments--made at lightning speed, each subtle movement of muscle, bone and
feather in wondrous harmony.
These birds are not flying. Flying is flapping wings to propel the bird forward. Each vulture is making adjustments at incredible speed -- the
result allows the bird to stay aloft, in the same general area, without burning precious calories needed for great flapping movements of the wings.
As the wind gusts and wanes they fold the wrist of the wing, spread their primaries at the wing tips, fold and lower the broad tail feathers, smooth
the small coverts -- constantly rearranging the surfaces touched by the wind. At times they roll their bodies, tip both wings to decrease the lift;
in this attitude they slip downward and to the side, take up a new station a short distance away at the same height.
Now I can begin to understand what they are doing. The new and bigger question is "Why in the hell are they doing it?" The second Bloody Mary helps
me get closer. I let my mind and body drift aloft, enter the spirit of the black weavers. I imagine being buffeted by the wind gusts. I tighten my
small shrunken thumb, slightly folding a wing as the wind abates. Tiny muscles are now moving my wingtip primary feathers to stabilize my horizontal
attitude.
A breakthrough, a revelation. The big birds are using no more energy to make these miraculous adjustments than I do when I turn slightly in my
chair, toward the beach, to see a passing boat. Now some eduction is called for: these birds, just above my head, have been in the air all morning.
Since they have sharp eyes and an uncanny sense of smell (they can smell carrion from hundreds of feet in the air to a radius of five miles) they
would have discovered anything edible on the ground after the first few minutes. If we rule out this stationary routine as a part of mating, it can
only mean that the birds are up in the wind to regulate their body temperature and to conserve energy/calories. They eat on the average of two to
three times per month. It may be that they use less energy aloft, on the wind, than when at rest, roosting on the ground or on a cactus. On cold,
wet mornings I have seen them stretch their broad wings to catch the morning sun -- the same birds hold this Kodak Moment pose, let the breeze
dissipate the heat from their wings on July and August afternoons.
All this study has heated me up. I put down my glass, walked to the outdoor shower for a cool change of pace, walked cool and dripping back to the
lounge, resumed my studies. Now things are taking a very different perspective -- these birds were roosting, sensed the wind, HAD to go aloft to
conserve energy for as long as possible; to live another day to hunt for scarce roadkill. It's like they have a job. They dare not stay on the
ground, on the roost if there is an opportunity to conserve energy or body fat -- their lives depend on their being able to use the wind whenever and
wherever possible. This grand freedom I have so envied turns out to be a life-or-death injunction, not a flight of fancy.
Two of the beasts are now hovering very low, close to my position. They are c-cking their ugly, red heads to get a better look -- the eyes have a
nasty leer -- curiosity? Did we, however briefly, trade places? While my mind's eye floated with them, did they sense, if only for seconds, my
mystical intrusion, drop down to enter my cooler world? Could it now be envy?
I'll make sure tomorrow. I may bring out a little bucket of ice, make some more Bloody Mary's --- this time with real blood.Sharksbaja - 4-1-2008 at 07:45 AM
APRIL FOOLS!David K - 4-1-2008 at 08:10 AM
Here's one Graham!
(Neal Johns photo)
and here's one at L.A. Bay, photo'd in 2002:
[Edited on 4-3-2008 by David K]Graham - 4-1-2008 at 09:24 AM
Thanks David. Good to see my red headed cousins.
Osprey, great writing. Wish I could capture the moment like that. But be careful about overdoing the Bloody Marys or you’ll start seeing double.
Sharks have a fun time at jury duty. Thanks for the suggestions. And thanks Taco, Pompano, and Mexitron – all good points.
Apart from a few isolated palm canyons, the island is certainly devoid of water, so much so that there are almost certainly no coyotes living there.
I’ll have to do a little research and see how much water a vulture needs say in comparison to a raven.
I’m sure the lack of food is not the answer. The island beaches are rich in carrion. Dr. Gary Polis and Michael Rose of UC Davis, who tragically died
along with three Japanese scientists when their boat overturned in LA Bay in March 2000, calculated that each yard of shoreline in the area receives
an average of 60 pounds of “detrital algae and animal carrion” each year. And it was hard for me to walk a mile under the cliffs or on the beaches and
not see a washed up sea lion, dolphin, or Humboldt squid, never mind all the dead birds and fish.
The island is very rugged, the high point is over 4000 feet and judging by all the high flying hawks and frigate birds, there were plenty of thermals
to stay aloft.
What is peculiar about Angel de la Guarda is the number of feral “vampire” cats out there… and judging by all their tracks they often were circling
around my tent when I was sleeping soundly… somehow they seem to get by with little or no water. Anyway, they are clearly having a huge impact on the
wildlife of the island, and might possibly have driven the endemic Angel Island deer mouse and other rodents to the brink of extinction…
So it doesn’t seem impossible, that they may be adversely affecting the vulture population and letting the ravens get the upper hand… or wing or
whatever. Gracias again for all the input.
GrahamFatboy - 4-1-2008 at 09:44 AM
Quote:
Apart from a few isolated palm canyons
Is there standing water there in any of those canyons?
Quote:
Anyway, they are clearly having a huge impact on the wildlife of the island, and might possibly have driven the endemic Angel Island deer mouse and
other rodents to the brink of extinction…
Cats, rats and goats sure do play havoc with local isolated ecosystems!!!!Skipjack Joe - 4-1-2008 at 01:07 PM
Are there any settlements on the island? If so are there vultures near them? I'll wager there are not.
I think that vultures benefit greatly from people and their populations are far greater than they would be otherwise in baja. I see vultures at dump
sites, at highways eating road kills, and at fish cleaning stations. For example, the palm trees at San Lucas Cove are lined with vultures waiting for
pangueros but I don't see them at San Marcos island, just 5 miles away (even though there is a colony of seals nearby).
Crows and vultures have different requirements I believe. Crows can get by eating a variety of things and can hunt to a degree.
So, I think it's the relative lack of food that makes vultures scarce at the island. I don't think it's feral cats.Graham - 4-1-2008 at 11:19 PM
I didn’t see a drop of standing water on the island except immediately after a morning of rain. But I didn’t get over to the palm canyons. Some of the
kayakers and car toppers that I wrote about, who did visit the canyons, sent me pictures which show palm trees but no obvious water.
And Skip you make a good point about ravens being able to hunt as well as scavenge. Several times I witnessed them working in concert trying to drive
ospreys off their nests, presumbably to get at the eggs and chicks. But on the other hand, in spite of all the protections afforded the island, I
shared campsites with several groups of poachers from the mainland. At the time they were clearly visiting the island with impunity and told me they
had been doing so for years. After a night of diving, the shore next morning would be littered with their fish guts, lobster heads, shucked clams,
etc. And the birds would be there in abundance – gulls and ravens mostly, but not a vulture! There used to be a huge scallop camp on the island with
as many as 1500 residents, at a time when LA Bay had a fraction of that population. According to the former residents I interviewed, the camp
activities were attracting veritable plagues of sharks, rattlesnakes, and flies, so I have to keep an open mind about there being insufficient food
for vultures.
I’ll probably have to visit some remote islands without feral cats to see what extent turkey vultures are present or absent.
Appreciate all the good points.Mexitron - 4-2-2008 at 03:43 AM
Doesn't seem likely, but perhaps a lack of the vultures prefered nesting sights contributes to their scarcity as well.Pescador - 4-2-2008 at 08:40 AM
Skipjack is right, I live just south of San Lucas Cove and we also have a ton of birds on the shore but I have yet to see a buzzard on San Marcos
Island or Tortuga for that matter where I spend a lot of time. I will question the locals to get their take on this. I know they could fly there if
they were so inclined but for some reason they must opt to not do that. On San Marcos Island their are full time residents on the gypsum mine and
they also have a dump which should attract these birds but I can not remember ever having seen them. I will have to get a pitcher of bloody marys and
do some serious scientific study on this.Graham - 4-2-2008 at 09:38 AM
Thanks Pescador and Skip. That San Marcos Island observation is really interesting. Unless San Marcos is overun with feral cats from the settlement
out there, I may have to amend the cat theory.
I like your approach to scientific study. Let us know the results.Skipjack Joe - 4-2-2008 at 09:41 AM
Graham,
The reasons I don't think it's feral cats is because:
1. there are lots of cats around the developed areas on the peninsula and the birds seem to be fine.
2. there are other birds on the island and they seem to survive with the cats.
3. there should be cliffs and ledges where birds should be safe from cats.
If food is not the limiting factor then perhaps they do have difficulty soaring over open water. I thought that perhaps they need those warm updrafts
to soar. They like to follow the cliffs along the shoreline very often. But I could swear remembering laying on my boat in open water and seeing them
far above, a dot in the sky. You would think that crossing 5 miles of open water would be simple.
Competition? I've never seen frigatebirds molest them. They really occupy different niches.
I still think it's lack of sufficient carrion. In a natural setting these birds need a lot of territory to support them. Perhaps the carrion isn't in
the right state for them to eat. Maybe gutted fish and animals are just right but others are not. Perhaps they prefer freshly killed animals and won't
touch partially decomposed matter. Perhaps they only eat fish because anglers have done all the work and warm blooded animals is what they would eat
under 'natural' situations. They definitely have some preferences. I've never seen them eat the dying squid we find everywhere. Need to understand
their feeding habits better before making any judgements. There's probably stuff on the internet ....bajalera - 4-2-2008 at 06:19 PM
I think they're scared off by the lady vampire wearing the white dress, the one who usually walks the backroads at night.
Nice buzzard essay, Jorge.Roberto - 4-2-2008 at 08:36 PM
Quote:
Originally posted by Graham
There used to be a huge scallop camp on the island with as many as 1500 residents, at a time when LA Bay had a fraction of that population.
I believe there was also a fish camp just off the north end of the island, on Isla Mejia. No permanent settlement in modern times that I know of.Pescador - 4-3-2008 at 09:45 AM
This is really interesting, because I do not think it has anything to do with food. At San Marcos Island there is a dump which is a typical Mexican
dump with lots of food available but no one that I have talked to so far ever remembers seeing a buzzard there. I think it may have to do with the
issue of flying over water. In fact, now I am curious as to whether or not they fly to the closer islands within a mile of shore.
Now, Skipjack may be right about the soaring behavior over water and it is easy for our larger brains to understand soaring distance, but the
buzzard must not have a flight computer which lets it know it could reach the islands and has come to stay on shore.Graham - 4-3-2008 at 11:07 AM
Roberto, I think you are right on both points.
Certainly there was no permanent settlement on Guardian Angel Island. The scallop camp that I was referring to operated in the early 1970s. It was in
the SE corner of the island just above Isla Estanque.
At its peak, there were over 200 pangas operating. It was more like a village or small town with several stores, families were living out there,
keeping pigs and goats. You could get much better food and produce on the island than you could get at LA Bay at the time.
An enormous amount of trash was produced, including fish and scallop remains. At first it was all dumped in the sea, but that didn't please the divers
as it attracted a lot of sharks to the area where many of them had to spend hours underwater performing more controlled ascents after brushes with
decompression sickness. So a truck was brought to the island and most of the refuse was trucked to inland dump sites.
And Pescador you are definitely providing food for thought.
I have witnessed gulls mobbing and driving vultures to the water if they come too close to their nesting areas. In fact, I tried to rescue a vulture
in the water off an island in Bahia Concepcion. It was being attacked by several gulls and was close to drowning. I got it up on my sit-on-top kayak,
but the persistent gulls knocked it off again and eventually drowned it. As I paddled around I found several other turkey vultures dead in the water,
perhaps having met a similar fate.
Being over water near a gull nesting site is clearly a dangerous place to be if you're a vulture.
Thanks, Graham
gulls and vultures as competing scavengers
Skipjack Joe - 4-4-2008 at 05:31 AM
Quote:
Originally posted by Graham
I have witnessed gulls mobbing and driving vultures to the water if they come too close to their nesting areas.
This made me think about the role gulls play in the whole thing but from a different perspective. If you drive along the highway north of the
immigration booth at GN and you encounter a road kill (cow, coyot, rabbit) you will invariably find vultures feeding on it. This despite the fact that
you're a half mile from the pacific. If you drive the half mile to the waters edge and find a dead spotted bay bass or corvina it will be the gulls
pecking at it. If you drive south to the fish cleaning stations at SLC you will see both vultures and gulls eating the fish that's tossed at them. In
the absence of man I think gulls are superior competitors for seafood than vultures.
Now lets consider an island in the cortez. Here there is an abundance of seafood right next to shore. The gulls become even more concentrated to the
point of nesting. They effectively greatly diminish the vultures ability to feed on what the sea delivers. So their effective feeding territory
becomes the island interior.
To me, the fact that vultures soar is a big deal. It means that in it's natural state the bird requires a lot of territory to sustain it. It glides
because it just doesn't get enough food to actively beat those wings in pursuit of a meal. It's a weak competitor. It gets by on whats left over after
everyone else is through.
It needs a certain amount of territory to sustain it and if the shoreline is removed from the islands then perhaps the remainder is not enough to
support a thriving population.
If that's the case then not all islands are alike. La Guardia should come closer to having the resources than say, La Raza, with it's huge gull
population and no inland foraging territory.
Food for thought. Although the picture is getting clearer in my mind.windgrrl - 4-4-2008 at 06:18 AM
..saw absolutely scads of turkey vultures near Los Barriles mid-Jan.Crusoe - 4-4-2008 at 08:04 AM
Skipjack.......Good work. I think you have pretty much nailed it.Bird behavior is very fascinating stuff. Also in my travels I have observed that some
birds such as crows and ravens absolutley do not like saltwater.This could be why you never see turkey vultures totaly immersed in saltwater and
diving and feeding like ospreys and eagles. A bird bioligist I knew once compared them to chickens and roosters. They sure are fun to watch soar.++C++mtgoat666 - 4-4-2008 at 04:01 PM
Quote:
Originally posted by Graham
Where were the turkey vultures???
Anyway, there are not many places in Baja where you won’t see a vulture in two months. In my new book I took a wild guess as to why this might be so,
but I’d appreciate any insight or suggestions…
Educated guess,... vultures are predators to eggs and bird chicks, and vultures are are probably driven from the island by the birds that nest on the
island, gulls perhaps.
Feral cats on the island sound like an ecological nightmare, but may be keeping rats in check, which rats would be an equally bad ecological disaster
if not kept in check by feral cats. Cats and rats have probably driven a few bird species from the island.
Every species has its niche -- and mans activities do a fine job of tweaking everybody's niches.Graham - 4-4-2008 at 10:47 PM
Wonderful feedback. Thanks Skip, Mtgoat, and Crusoe for all the great information and suggestions. I'm heading to LA Bay for a week or two... with a
very open mind.Pescador - 4-7-2008 at 02:15 PM
Well, I was wrong, there are turkey vultures on San Marcos Island. I was over there today and went to the windward side and definately saw at least 4
or 5. I had not seen them on the one side of the island, but they were on the east side and the wind was blowing from the east so it made some good
ridge soaring for them.
off-limits to
the general public. Drug runners rarely clean fish ya know.
