Wednesday, June 2, 2010
7:11 PM | Posted by Sweep Commander | Edit Post
Neither the Maganrord team nor the island's legit biologists can find the juvenile raven anywhere.
We last saw it on Sunday perched in a cypress tree eating an unknown food item. It had made an enemy of a California gull that buzzed it persistently to no effect. The most the gull could elicit from the fledgeling were a few low vocalizations.
The next day, it was gone, either fledged or dead. The bird flew well and it is now believed to have predated a western gull nest, so it appears to be more than capable of fending for itself. Also, though it was a bird in it's first year of life, it was significantly larger than the typical raven I observe on the mainland, just like mom and dad:
For size comparison's sake, the adult raven on the right and the human being on the left were equally distant from the camera as took this picture. Well... not really, but our ravens are still huge.
At any rate, though raven breeding season appears to be over, the pair is not taking a vacation. They have been actively collecting nesting materials in recent days and have been seen transporting them back to their home tree. I caught one collecting moss, presumably for nest lining.
Why would the ravens be working on their nest structures? Breeding season is over. Right?
Well, the nesting structures were examined earlier in the year by our park's biologists and portions of them were tampered with or disassembled in the process. The ravens may simply be rebuilding what was destroyed.
Also, nests must be repaired each year as the hatched chicks defecate inside the nest, but it's very, very early for that process to begin. Nest construction and repair usually occurs in the spring.
A more alarming conclusion might be that these birds are making preparations to lay a second clutch. It's hard to imagine that the moss lining they're collecting could keep from year to year and ravens will sometimes lay a second or even a third smaller clutch if the first one fails, but as far as we know the ravens did successfully fledge a single bird this year and it's awfully late in the season to lay new eggs.
We'll keep watching, however, because our giant and wily ravens are not to be underestimated.
Here's a video we took today of one of them eating a gull chick. As usual, sorry for the camera shake.
- Raven male defends his young; raven female is... w...
- Baby birds on Alcatraz are risky ventures indeed
- A Coda on the Falcons of Alcatraz
- Nesting season update on Alcatraz's newest western...
- New post!
- Juvenile raven found but strange question remains....
- Mystery solved...
- It's a mystery!
- Juvenile raven vanishes, breeding parents set to w...
- ▼ June (9)