Tuesday, December 11, 2007

CORVUS COURTSHIP

Another beautiful day! The air is crisp (for L.A.) and I think we are finally done with the little surprise heat waves, which makes it seems more like winter. There were some scattered clouds this morning, including one big one that looked like the underside of a cumulo-nimbus; it was tinted a rosy-orange from the rising sun.

It’s been so cool in the mornings that I’ve switched around my walking schedule from early morning to lunch time. Of course there was quick reward in this as I witnessed the most amazing bird display ever yesterday.

I was walking over near Moore Hall (one of the original buildings on campus) and I heard some strange knocking and croaking noises, which sounded like the strange noises crows sometimes make; only this was louder and weirder. I followed the sound by walking up the lawn on the north side of Moore until I got to a large tree next to the building. There, on a top-most branch, was a pair of Common Ravens (Corvus corax), one a bit larger than the other, and they were obviously in the midst of some courting behavior.

They sat very close together and took turns vocalizing this odd croaking-knocking sound that ended in a kind of soft whistle and when each did, it would spread its wings slightly, ruffle its neck feathers and dip down in a sort of curtsy. I watched them for about fifteen minutes and this activity continued nearly unabated. Yet another time when I wished I had a video camera with good sound. This was really an amazing and unforgettable sight!

To confirm what I’d seen, I went online to see what I could find about this unusual-looking behavior. It took a bit of sleuthing, but I found the following, which was exactly what I observed:

COURTSHIP:

“Courtship displays…include bowing with elongated neck and fluffing throat feathers. Male has fanned wings and tail, stretching its neck upwards while is bowing with bill downwards. Sometimes it…performs preening on female’s head.”
[http://www.oiseaux.net/oiseaux/passeriformes/common.raven.html]

“There is little information on when or how pair formation occurs. Displays occur between individuals throughout the year, some of which may be courtship. These displays are most intense in the fall and winter. There is evidence that pairs stay together throughout the year but no concrete evidence that mating occurs for life.” (
Boarman and Heinrich, 1999)

[Berg, R. and T. Dewey. 1999. "Corvus corax" (On-line), Animal Diversity Web at http://animaldiversity.ummz.umich.edu/site/accounts/information/Corvus_corax.html.]


VOCALIZATIONS:
“Common ravens are very vocal animals, with a diverse suite of calls and non-vocal sounds for different purposes and social contexts. From 15 to 33 categories of vocalizations have been described in this species. There are alarm calls, comfort sounds, chase calls, and calls designed for advertising territories. Common ravens may be able to mimic sounds of other animals but this has not been unambiguously documented. It is also possible that they are simply capable of a huge diversity of sounds and innovation enough to create calls that sound like those of others. Young birds engage in vocal play, in which they seemingly go through their entire repertoire of sounds, pitches, and volumes for minutes or hours at a time.” (
Boarman and Heinrich, 1999)
[ibid.]

Nature surrounds us, even when no one is paying attention. I am glad that I am blessed with curiosity and that my senses have always been attuned to the wonder that surrounds me, even in places that most people would not even suspect or be aware of.

So get out there folks! Open your eyes and ears! Take a walk to clear your mind and renew your spirit. You will be rewarded, as I so often am, with little glimpses into Nature’s wondrous cabinet of curiosities.

Have a wonderful day!

Peace,
Navroth


[Written while listening to Dead Can Dance "Into The Labyrinth."]

Addendum: On Friday, Dec. 14 I spotted the same pair, in the same tree. I was out walking and heard the strange knocking call as before, but only once. In the ten minutes that I watched, the two birds sat quietly but really close together, while one appeared to be brushing its head against the other's. They are obviously a mated pair.

I also saw a huge nest of twigs and leaves in the uppper branches of Italian Stone Pine on the S. side of the Janss Steps. Could this be their nest or is it an older one? I don't recall seeing it before. I shall have to keep a close watch on these two!





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