Sunday, December 29, 2013

The Antelope Valley is Going to the Dogs (that is, I mean to the Crows)

The Recent Arrival of Crows in Lancaster and Palmdale

There's a change going on, as one species begins to replace another --- I am talking about the recent arrival of crows. 

Most of us know that the Antelope Valley has a LOT of ravens. On any given day you can hear them, see them, watch them build their nests on freeway signs, and you even may have to shoo them out of your garbage bin. Other than a few landfills in Alaska, it's hard to find anywhere in America that has more ravens in a ten-mile radius than does Lancaster. They love all the things we provide: garbage, roadkill, nesting cliffs (also known as highway signs and tall storefronts), and thermal updrafts to soar on as they circle effortlessly higher and survey their domain. Ravens have been here at least since the end of the last Ice Age, but like raccoons and probably coyotes too, their populations surely have increased with the arrival of quote unquote civilization in the past 100 years.


Crows, in contrast, rarely occurred out here. As compared to ravens, crows are smaller, have squared-off tails (when seen from below, in flight), have slimmer beaks, and mostly go caw-caw-caw. (Ravens have a harsher, more croaky sound, though they also make gargling noises and klock klock klock and so on.) It used to be, going to L.A. to do research at UCLA or visit friends, I knew I had arrived "down below" when I could hear the crows in the trees. I didn't even have to look up in order to know I was in a different place.

Out here it was always different. For many years, one could go all year and not run into a single crow in the Antelope Valley. Then for a while, they were one corvid out of a thousand. A corvid is either a crow OR a raven, as a general group, like the fact that humans and chimps are both primates. Most corvids here were ravens but once in a while, there might be the stray, oddball crow mixed in --- as I say, 1000 ravens for every 1 crow you came across. Cal Yorke and I can still remember when "crow" got added to the official AVC bird list. (Well, actually, it was "American Crow," our particular species. In proper ornithology, it would be typed with a capital A and a capital C, American Crow. It's sister species properly typed is Common Raven.)

The old ratio seems to be changing. But before we talk about this week's "invasion of the crows," let's quickly review which one is which --- after all, you want to know yourself, right? Impress your kids, wow your friends by being able to correct them each time they get it wrong.

Here is a page spread from the National Geographic Guide to Birds, showing the different kinds of crows and ravens in North America, and showing maps of their ranges. Crow in flight is at the top right, with the more squared off back edge to the tail, and the raven is bottom, with the more wedge-shaped or diamond-shaped tail.


Here in Southern California, there is usually a fairly reliable range separation too, or at least, there used to be. Around the Los Angeles basin, crows were usually found in "nice" places --- they liked beaches and lush neighborhoods and settled farmlands. Coming up the 14, one left the crows behind at the In n Out Burger on Sand Canyon, well before Canyon Country and Acton. Heading northwest, if one took Highway 138 out of the Antelope Valley towards Gorman, the first crows usually did not turn up until you got to the Lebec Rest Area near Fort Tejon. They then became dense up 99 past Bakersfield and through the Central Valley. Ravens and crows can be found together, but you mostly expected crows down in Los Angeles proper and ravens in the deserts.

Here is classic crow habitat in Southern California.


In contrast, ravens favor harsher, more wild conditions --- they are birds of mountains and deserts, cliffs and salt flats. If you are in open rangeland like this shot from Nevada, there never will be any crows, only ravens.


And since the open range shot more classically describes the Antelope Valley than the beach shot from Santa Monica does, you can see that we would expect to have ravens, not crows, resident locally, as indeed was the case.

I suppose that fits with our "wasteland" image. Since we're thought of as a body-dumping sort of place (a cross between the New Jersey Meadowlands of The Sopranos and a survival show set in Death Valley), ravens somehow fit the profile. And crows and ravens as a group are associated with ill-omen, death, misfortune. The group noun for a flock of crows is "murder." As opposed to a pod of whales or a pride of lions, one correctly says that it is a "murder of crows." The collective noun for ravens is to say not flock or herd or gang or flight, but that it is an "unkindness" of ravens. Bad press indeed! They need new management teams.

So just look around --- of course we would not have the crows of Beverley Hills, but instead, the ravens of Littlerock.


This is just our own cultural hangup, of course, not any indication of actual malice or evil. We are a culture that also hates wolves, is afraid of the dark, and that thinks that all bats carry rabies and want to get into our hair.

Other societies have a different view. In Inuit culture, the raven is a trickster character, brimming with sexual energy and mischief. He is somebody to watch out for (he might want to sleep with your wife) but he's also to be envied for his ability to play pranks and get the best of any situation. He is a survivor, a bad boy but in a fun way, sort of the Jack Nicholson of the bunch. This illustration is by Cape Dorset resident Echalook Goo, and dresses up the birds with the colors perhaps they they see in their own minds.


That just goes to show that it does not have to be a cemetery all the time, any time we want to think about wildlife. It is just here in the classical Judeo-Christian tradition that ravens and crows are associated with melancholy and death --- remember for example that the famous Edgar Allan Poe poem is not called "The Mockingbird" or "The Sparrow," but "The Raven." That seems a bit unfair. Here is a very well-drawn crow, grim and dead, from an Andrew Wyeth painting, Winter Fields. If he had shown a dead cardinal or a dead puppy, he might have had the Humane Society after him. But a dead crow? No problem --- they represent death already, so what better irony than to see one stone cold dead. Nobody objects to an image like this. There is no "save the crows" society.


We actually should praise crows and ravens for being the clever and varied beasts that they are. They can count to seven, use tools, remember enemies for years and years, and play in the snow just for the fun of it. Ravens mate for life. Here is a note from artist and author David Sibley. "Ravens [in a lab] faced with a novel task, such as getting food that is dangling on the end of a string, were able to assess the problem and then use their feet to hold the string and pull the food up." In other words, they pulled in slack with their beaks like a fisherman reeling in line, held the slack in place with their foot, and then pulled in more slack, until the food was all the way up on the branch. "They performed this action without missteps the first time they attempted it." Smart birds indeed!

Crows and ravens are related to other corvids, the jays and magpies. World-wide, there are over 100 kinds and the group shows a really interesting diversity. Here, look at these Green Magpies, from Vietnam:


As this illustration shows, corvids do not always limit themselves to goth black. Even ravens come in different patterns. One of my pleasures on a trip to Ethiopia was getting to see one of these guys in the wild, Ethiopia's endemic Thick-billed Raven. Note the snappy white beanie. For once, the common name matches the beast exactly. That bill is like some kind of medieval poleaxe or halberd. 


This illustration above and the next one below come from the same book, Crows and Jays by Madge and Burn, as did the green magpies, above. The corvids are such a diverse group they have enough species to merit their own book. The book describes bright green "blue jays" and other kinds of jay found only in the remotest parts of the Amazon.

I hope to go to Tibet next summer, and if that trip comes together, one species I will look for is a very strange jay indeed, the Bidduph's Ground Jay.


That one has a very restricted range, listed as "Tarim Azne east to Lop Nur," on the China / Tibet border. According to the book, it is shy and elusive, running away over sand dunes or diving into scrubby bushes to hide from people. It's one rare blue jay!

One corvid that doesn't mind hanging out next to people is the Indian House Crow. This kind will ride on the backs of cattle, stowaway on cargo ships, gather by the hundreds on tall buildings to play chase-me and loop-the-loop, crack open nuts by dropping them on the concrete, and at least in one instance, steal golf balls from games in progress, seemingly for the pleasure of watching the golfers wave their hands and chase after them. Here's a pair on the beach in an outer atoll of the Maldives. (I was careful to protect my golf balls.)


The Indian crows bring us back to the crows of Palmdale. It's trash day today as I write this, and as usual, some of my more prolific neighbors somehow have more trash than the rest of us, so much so that they cannot close their trash cans' lids.

Leaving bags of trash exposed like this will bring ravens from far and wide, since they can easily slice open even the toughest Hefty bag, and they will have a feast as the mess spills down onto the street. It's bad for the birds --- this is not a healthy way for them to live --- and untidy for the neighbors, whose yards will become filled up with trash as the wind blows things away. One thing about ravens, they are not big on cleaning up after themselves.


Trash day used to be raven day, but now it's crow day, too. All winter I have been hearing one pair of crows on my block. Whether they came up the 14 from Los Angeles or down from Bakersfield and Tehachapi I am not sure, but each morning all winter I have heard this one pair of crows vocalizing and chasing each other up and down the block. My wife and I keep an informal list of all of the birds we have seen from our house, and it's up to 54 species now. One of the first birds on the list when we moved in was raven. Now, as of this winter, the list includes American Crow.

Not only are crows becoming more common, they are starting to gang up on the ravens. Many species of birds participate in what's called mobbing --- getting together like an angry gang of peasants with pitchforks and torches, ready to drive away an intruder. Here is a picture of crows mobbing a Great Horned Owl.


This comes from The Sibley Guide to Bird Life and Behavior by the National Audubon Society. The caption says this: "American Crows mobbing a Great Horned Owl. All corvids are rather noisy and bold. Traveling in small groups, they mob predators with belligerent calls and cautiously aggressive actions. This behavior serves the purpose of alerting other animals to the presence of a predator and in many cases is sufficient to drive the predator away." You probably have seen this too, especially in the spring when parent birds want to protect their nests. Blackbirds will chase ravens and even full-grown hawks, harrying them until the larger bird gets tired of the hassle and soars away.

In my neighborhood today, we had a gang of 6 crows, and they were busy beating up 2 ravens. One-on-one, no crow can match a raven, which has larger size, longer wings, and a much heftier beak. But as a group, the crows were being very territorial, saying (in essence), "This is OUR garbage, sucker!" Here is my photograph from this morning.


The top bird is a crow (note the more squared-off tail), the middle one is a raven (note the wedge-shaped tail), and the bottom one is a crow as well. They look as big as the raven because they are closer to me while the raven is a bit higher in the air.

The reason the top crow is missing a wing feather is just normal molt: as feathers wear out, they drop away and regrow, usually on left and right wings at the same time, and usually just one pair at a time, so the bird always can fly even as new ones grow in. It's possible that feather got snagged on a branch or a cat got it, but most likely it is just a normal sequence of molt and replacement. I doubt it's a wound from the raven, since in their feints and jabs, none of these birds ever made actual contact. There was a heck of a lot of cawing --- nobody ever accuses a crow of being too quiet --- but no direct contact.

This makes me wonder, what has changed? Why crows now? They are not undergoing a particular range expansion nation-wide that I know about. What it may reveal is that trees and landscaping in the Antelope Valley are maturing. For a bird that size to do well, it needs more than roadkilled coyotes. It needs fruit trees and dead squirrels and half-eaten cupcakes and compost piles and tall, dense hedges in cemeteries.

Our property values may not mirror Santa Monica's, but perhaps our backyard plantings now do. My tract was built in the mid-80s, so most of the trees are not much older than that. We have the usual California urban mix ---- eucalyptus, mulberry, Bradford pear, Japanese plum, some London plane trees, some Italian cypress, and so on --- and some of these are now quite substantially filled out. Almost all the houses have trees, and almost all those trees look "full grown." And crows don't nest on cliffs or pseudo cliffs --- unlike a raven, you won't find a crow nesting on the Ave H exit sign on the 14 freeway. They will use telephone poles but prefer the crotch of a tall, bushy tree, the kinds of trees that now we finally may have started to provide.


Or maybe it's not that, but that I have some neighbor I don't know about who leaves a lot of cat food out. Maybe winters are a bit less frosty overall. Maybe we leave out more trash on trash day. Maybe the raven population has been attacked by a disease or parasite, or maybe it's that my local ravens have shifted over to the west side of Palmdale, to be closer to the landfill, and so crows have moved in to fill the void that way. Animal populations reflect a wide spread of dynamic factors, and it's rare than a trend can be traced to a single cause.

What I do know is that nature is never static, and one reason to keep a house list such as I do is not to set any records (other birders have house lists in the 300s), but just to have a reason to be a bit more aware, a bit more attentive to the world around me. Crows and ravens look and sound enough apart that you can distinguish them without binoculars, but to do that, first you have just to start looking and listening in the first place.

It's an interesting, ever-changing world out there, and this week's invasion of the crows reminds me of that all over again.

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The AVC Blog is curated by Charles Hood, and he can be reached at chood@avc.edu. It does not represent any official position by the Board or the District about the correct way to use a garbage bin, about the poetry of Edgar Allen Poe, or about which is prettier, our raven or Ethiopia's.

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