Showing posts with label WEGU. Show all posts
Showing posts with label WEGU. Show all posts
Sunday, March 14, 2010
Falcon dines again (Also: Comments Fixed!)
Now to the meat of it.
She looks happy. As usual, there are more pictures of all sizes on my flickr.
Sorry for the graininess on these photos and videos. These photos were taken utilizing a ridiculous level of optical and digital zoom. I love my camera. It's not the $3,000 body and lens setup I dream of, but somehow this combination of 80x zoom and a tripod can yield somewhat intelligible images at great distances.
It's unknown what this prey item was. Several white feathers fell from the smokestack as she ate. Several of my final images of her eating show her standing on a white feather, presumably from her quarry.
Here are a few very short videos of her dining.
I guess it wouldn't be a proper MAGANRORD post without a falcon video with semi-humorous narration.
In the following video, she finishes up and departs.
I was truly struck by just how red the meal left her beak and talons.
Also, the white feathers invite a bit of curiosity. The only prey item available that yields consistently white feathers is a gull, and our gulls are probably a little too big for her. Pigeons can be lightly plumed, so that's possible, though every feather I saw was as white as snow so I'm a little bit skeptical of that possibility. Our snowy egrets haven't returned yet, so they're ruled out.
Peregrines do scavenge and dead gulls have been turning up on Alcatraz. There were two such departed on the roof of the new industries building this afternoon.
Whatever the prey was, the female filled her crop and there were leftovers:
If the female abandoned her bird without finishing it, it may have been a large bird, like a gull or it may reflect her assessment of available prey. Slim pickings will mean a thoroughly devoured corpse. Abundance means she eats her preferred parts and leaves leftovers for others to scavenge.
Who says corvids and falcons can't be friends?
Also, meet this guy:
I saw him duke it out with another WEGU in a half hour brawl over what a visitor who witnessed the madness said was just a morsel of food. The whole thing made me positively squeamish and I think it led to some rather shaky camera work as I recorded the encounter.
I'm going to post our 26 minute video in the coming days. I don't expect that anyone will watch it but I do want to make a point about the gull's way of life. It's awful. It's not all mating and gloriously forcing down huge starfish. It's a lot of senseless violence. Ounces of blood and a half hour of combat leaving both gulls exhausted seems like it isn't worth a bit of chicken, which is readily available to these gulls.
Stay tuned.
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Monday, February 22, 2010
Falcon News and Lucky the WEGU!
'WEGU' is bird nerd speak for western gull.
Here's your Alactraz birding update:
- For a number of weeks now, an injured juvenile western gull has been living on the west side of the island, hobbling about near the old prison incinerator. When I first observed the individual, I thought he or she would surely starve or be killed by an angry adult, tired of the endless begging for food. Somehow the bird has endured and because of this very good fortune displayed the enfeebled gull, I've decided to name it 'Lucky'.
- Fellow western gulls respond to Lucky in the same way that the typical city dweller responds to a homeless person aggressively trying to hock copies of The Street Spirit. As he/she whines hoarsely and desperately pecks at their lower mandibles in an attempt to force them to regurgitate food, the mature birds shift their gaze, looking to the side or at the soil as they go about their business or walk fleetly away. They avoid looking Lucky in the eye as they evade or ignore.
- Curiously, the other western gulls almost never show an interest in harming Lucky. Once, I did see a gull try to deter Lucky's begging with violence, but another adult gull intervened, apparently to help the poor WEGU. I don't know whether the gull who intervened to aid Lucky was of any relation to him or her, but on the whole it struck me as a strange behavior for any western gull to display. These are not compassionate creatures.
- Several pairs of mallards have arrived on the island and from our observations over the last several days, these are some very sleepy ducks.
- The male falcon could be seen darting, diving and weaving inside a hostile mob of western gulls at around 4:30 this afternoon. Eventually it squirmed away and perched on the lighthouse.
- The female falcon has adopted a fairly predictable daily routine. More mornings than not, she perches on the water tower's railings facing west. When afternoon comes around, she moves to the other side and faces east. This may indicate a preference to face away from the sun, perhaps because direct sunlight interferes with her ability to perceive her surroundings or assess her prey.
Click on the image for a larger size
- After speaking with a number of former Alcatraz bird biologists, I've learned that falcons have been spotted on the island with regularity going back to the early 2000s, and perhaps earlier. As far as I can tell, however, it was assumed that any sighting was of an individual belonging to a known and established local pair, such as the pair that nest on the bay bridge. This year is unique because we've observed that we do indeed have a pair and we've seen them with enough brute regularity to surmise that they spend the vast majority of their time on Alcatraz.
Click on the image for a larger size
- I saw the pair flying together recently in high wind, performing yet more joint aerial acrobatics, spinning circles around each other, dive bombing one another and just doing a whole lot of what I'm assuming was falcon flirting. When one falcon disappeared, the other soared over a pair of gulls and aggressively fell towards one with talons extended. Gulls are not the fools of the sky, however, and this one simply executed an evasive falling maneuver of its own. The falcon then proceeded to approach the other gull in the same way with the same result.
- An adult western gull is probably a bit big for a peregrine to make a serious attempt to predate it. Rather, the falcon was probably feeling a bit feisty from all the courtship and hey, you've gotta direct that energy somewhere.
- Two western gulls aggressively chased a brown pelican over Alcatraz today, perhaps in an attempt to force it to give up its catch of fish. This behavior is called kleptoparasitism.
- Mourning doves and American crows have been spotted on the island in the last week.
That's it for today.
Sunday, January 31, 2010
The gulls return
click on the image to view it in a larger size
We'll see if they brought their dancing shoes. The gull population is swelling rapidly with courtship and territorial marking behavior now common among them.
Odds, ends
- There are several hundred cormorants in the waters to the west and north-west. Some of them were clearly of the double-crested variety. We saw western grebes and western gulls in their midst, and we're very interested in identifying members of other cormorant species in the mob.
click on the image to view it in a larger size
- Several porpoises were seen surfacing east of the island today.
- Last week, a heermann's gull was spotted on the dock. Though I missed it, I was able to positively identify it because one conservancy employee, thinking the gull was "funny looking", took a cellphone photo.
- For only the second time in two years, I observed a black oystercatcher on Alcatraz. Early last year, I spotted one near the dock. This time, I saw one flying over the bay near the island's east side.
Friday, January 29, 2010
Island's western gull males remind desirious females that Valentine's Day is a ways off
Thinking I might have the opportunity to document some early mating, I recorded this female, the smaller gull on the left, trying to entice her male. She positioned herself with her back to her partner and began the upward movement of the head seen in the video, along with the vocalization that accompanies it.This is how one western gull tells another that he or she wants food or sex.
However, just as I hit the record button, the male gull violently denied her, giving her instead a stern bite to the neck. This occurs in the video's opening moment.
We observed similar interactions among other western gull pairs, albeit without the violence.
Odds and ends
- Canada geese have arrived on Alcatraz. We can't be everywhere on the island at once, but our sense now that we're hosting around eight or so. The canada goose is divided into several subspecies and one of the next items on our amateur bird detective agenda is to find out what subspecies our geese belong to.
- The pigeon guillemots have also returned, seemingly going from invisible and absent to ubiquitous and loud in about a week.
- Brown pelicans now fly over the island with regularity. As recently as a year ago, pelicans not sick or injured avoided Alcatraz as if it were the center of evil and dishonor in the bird universe. While this isn't exactly a sensational observation, it's no less baffling for that. What has changed?
- Numerous brandt's cormorants have been seen on Alcatraz and in the waters around it. We can't wait to see if they return to breed.
- The common raven pair has been far less visible over the last week or two.
- The falcon had a bloody adventure recently. Stay tuned to MAGANRORD for BourbonHawk's upcoming post. Here's a little taste:
I wonder what she has there.
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