Nobody likes Ravens

Well, I do. But now I can imagine how they must feel.

Today our resident Ash-throated Flycatchers were on the attack. A raven, maybe a young one, flew low through our backyard, and a flycatcher dive-bombed his back. 'Squack'! said the surprised raven, waking up our dogs who also love to hate his kind. And stormed after him.

Pursued on the ground and from the air, the poor raven took shelter in an ironwood tree. His landing was so clumsy that he tumbled for a minute from branch to branch before he found his footing. A White-winged Dove flew by minding her own business, but the flycatcher were so enraged that they even attacked her. But then the Black-capped Gnat-catchers betrayed the raven, he left his perch, the Ash-throats chased again, and the raven  flew towards quarry and the Kestrels' Saguaro.

Too close! male, and then even female Kestrel picked up the chase.  Poor raven fluttered on, swooping falcons  above and below. But they did not go as far from their nest as the Ash-throats did - or were there 2 pairs of Ash-throats involved? Anyway, the raven finally made it back to the Eucalyptus tree where his elders were sitting, watching the chase, never moving a wing. Did they let him learn a lesson?

On Memorial Day Weekend, I was in Prescott for an art festival on the courthouse lawn. Ravens always live on the courthouse - it's their rock cliff fort. Very early on Sunday, one young one, by her behavior a female, was sitting on the lowest branch of an Elm-tree, chatting and clucking. Those ravens are pretty used to people.

When I imitated her clucking, she took no offense, but started to inch closer on her branch in coy little steps, then spreading her wings a little and making little bows. Her head got big and round with all its feathers erect, the iris of her eyes widened, and her clucking became a flirty cooing. From above a big raven scolded, but he stayed on the roof, just peering over the eves. The young one shook her feathers, all sleek for a moment, and cawed back. But then she became sweet and flirty again, and we continued our conversation. Until suddenly something hit me on the back of my head. Not hard, but noticeable. Then my shoulder, with the swish of feathers. I was pretty shocked at first because I thought the big guy had come off the roof .... but no, he was still just watching. But close to me, a nasal 'daeh- daeh-daeh' came first from one tree trunk, then the other ...

Then my attacker came racing around the tree:   a Nuthatch! The small, white-breasted bird ran up and down and around the tree, flew at me, then the next tree, then came back for more. I certainly don't look like a raven, but I must have sounded like one, German accent or not. So now I know how those ravens must feel ....

Bird Pointers

Artistic freedom: the ptarmigan covey is flushed. A good bird dog would NOT do that, he'd just freeze on point

In the late eighties I studied circulatory adaptations in the brood patch of Ptarmigan in Norway. To find these secretive birds, I often relied on the sensitive noses and natural pointing instinct of bird dogs. Every family in Trondheim seemed to own a couple of Setters or Pointers.

Pointing Gambel's Quail family click for better video quality

To my surprise, I recently observed very similar pointing behavior not in dogs, but in Gambel's Quail. Coincidentally, these birds are close relatives of the northern Ptarmigan. Both species are galliformes,  chicken like ground dwellers with short wings, strong running legs, and strong family bonds that outlast the breeding season so you find them all year round in their typical coveys.

This morning I watched a couple with two fairly grown chicks at the feeding station in front of my studio window. They were long and thin with excitement, their necks stretched and their beaks pointing. They held this pose and focused on a spot on the ground that from my view point was obscured by a rock and an agave. Clearly the chicks were learning to fine tune their maybe instinctive pointing by this concerted effort. In social animals, learning and memory are facilitated by highly-emotional situations. These chicks were learning their lesson well.
But what was triggering the excitement? Different from most bird mobs these guys were quiet and the other bird species were not drawn into the melee. The Mourning Dove seems hardly interested, the Thrasher keeps eating, only a sparrow seems ready to chime in.

Diamondback Rattler

But I got up from my desk and got my snake stick knowing exactly what was hiding under the agave. A Diamondback Rattler was tightly curled, absorbing heat from the warm sand and the morning sun. It is now so hot during the day that he is most likely night-active. The feeding station is visited at night by rodents, so this is a popular spot for rattlers.

This one was a small guy and his rattle didn't make any sounds. The small ones tend to wander straight west from that location, right into our dog run. So we decided to move him several hundred meters north. When he resumes his journey next night, he will hopefully bypass our house and the dog beds.

Curve-billed Trashers Rule!

Cuve-billed Trashers have many talents. They whistle at you like a street kid. They have a beautifully varied song that I like at least as much as that of the Mockingbird. They build a nest in the middle of a jumping cholla protected by thousands of barbed thorns, but are said to clip off the thorns that could hurt the nestlings. They are great parents that never tire of their very noisy, demanding fledgelings.   
But they are as fierce and aggressive as their yellow eyes and their sharp profiles promise.

A couple of years ago I watched this fight among a Trasher and a Gilded Flicker. Flickers are our largest woodpeckers here in the desert, and they easily drive the smaller Gila Woodpeckers from feeders and nesting sites. Luckily for the Gilas, there aren't very many pairs of Flickers. But in the case of Trasher against Flicker, the Trasher won.

But you have to watch what happens if a Trasher wants to impress his girl (and I don't think I' m anthropomorphizing very much here - shared aggression is a form of pair-bonding that can be observed in many species). Curiously, he never attacked the smaller Round-tailed Ground Squirrel, but he took on the giant Rock Squirrel every time the big guy tried to stuff his cheeks. When I filmed this, the squirrel was already a little desensitized to the attacks and seems to mimic a skunk, so the Trasher walks off, finds a new strategy and.....Just watch it.


The original video shows how the female thrasher joined the triumphant male after his victory of the quail block. Unluckily, the flickr version cuts off just before she arrives.  

Anyway, here they are, sole owners of the quail block of contention.

Cowbirds chicks and their foster parents

Since early March we've been hearing the flowing silvery song of Cowbirds in our backyard in the Tucson Mountains. We have two species here. The Brown-headed Cowbird has increased its breeding range from the Grasslands of middle North America to include now most of the US and Canada. The Bronzed Cowbird reaches us from its main distribution in Central America.

Bronzed Cowbird by NetSearchMedia

Brown-headed Cowbird by Ned Harris

Both species are brood parasites. Females lay their eggs in the nests of other species and leave it to the foster parents to raise the brood. Thus saving a lot of energy, female Brown-headed Cowbirds can lay more than three dozens eggs per summer. The nestlings hatch early and grow fast, so they have a competitive advantage over their nest mates and are usually the only ones to survive. Though foster species have some strategies to get rid of these brood parasites, they mostly just get conned into caring for the impostor.

Birds, like most animals (and humans for that matter) are programmed to react to certain signals with fixed behavioral patterns. Most of these signal are early evolutionary developments and therefore shared by many related species. Famous is the 'Kindchenschema' (big round forehead, big, wides-paced eyes, closely arranged features) that evokes maternal behavior across species lines in a wide variety of mammals. As kitschy dolls, Chihuahua dogs, and many cartoon characters demonstrate, these imprinted signals can be exaggerated to become even more effective, even to the point of corrupting the originally survival-based instinct.

'Kindchenschema'

The following anecdote illustrates this point. Last year I observed a cowbird chick following around after a female Hooded Oriole. The foster mother couldn't provide fast enough, the father seemed to be just watching, and she decided to feed the chick at one of our bird feeding stations (hummingbird feeders, fruit, water, and a quail block).
















There the chick got in the way of a hungry Curved-billed Thrasher. Thrashers are among the most aggressive visitors, even picking and winning fights with big Gilded Flickers (below) and White-winged Doves.




The Thrasher aggressively started towards the chick to chase it away. The chick hunkered down, flared its stubby wings, opened the huge yellow-lined beak, chittered excitedly - it begged. The Thrasher hesitated, then approached as if to feed the chick, then just turned away. Not exactly feeding, definitely not chasing, obviously confused and disarmed. Normally, a bird only feeds chicks that hatched in its own nest and that it is bonded with. The ueber-chick had nearly succeeded in crossing this line. I assume that Cowbird chicks are equipped with exaggerated begging-attributes, both visual and behavioral that make them simply irresistible.


This year we are watching the plight of a very small, but extremely energetic pair of Black-tailed Gnat Catchers. Their cowbird chick is already twice their size but still much smaller than last years Oriole fosterling. This time the male seems to be the more devoted parent, or maybe he's less camera shy than the female.















Individual Cowbird females seem to return to the host species that raised them. Some researchers believe that their eggs show similarities to those of the host. Last year, our Orioles were hit at least twice probably by the same female.
Now we have at least one new Cowbird lady around that likes Gnat Catchers.













Even though the Gnat Catcher female spent a lot of time in Creosote bushes full of seed pods, I don't think she figured out that she could just stuff the chick with those. She kept looking for insects instead. Cowbird chicks seem to thrive on a lot of different diets. As adults they return to a fairly vegetarian life stile, similar to that of other related Blackbird species.

I was first introduced to the intriguing behavior of Cowbirds as a postdoc at the biology department of the University of Trondheim, Norway. Researchers Arne Mosknes and Eivin Roskaft had turned from their brood parasitism studies of European Cuckoos to the American example, the Cowbird. Cowbirds are far more common than the more solitary Cuckoos and Eivin and Arne got to do research in a far warmer climate.

Green Heron at Agua Caliente

On May 5, after a long hot day of bug-hunting up and down Sabino Canyon, Eric Eaton and I decided to end the day with a stop at Tucson's beautiful palm-studded desert oasis Agua Caliente.


























Against the light of the setting sun, Eric spotted the sillouhette of a small Heron crouched on a dead branch over the still water. At first he even doubted that it was a bird at all because it was so motionless.





















The heron was intensely focused on his fishing. Ever now and then, his pose would freeze even more, he'd lean forward in nearly imperceptible increments until it seemed impossible that he would keep his balance. Only his strong, very long toes made this acrobatic stunt possible. Eventually, his head would shoot forward and the sharp beak would grab a small fish. While we watched he never missed once...



The birds at Agua Caliente are used to visitors and not too shy. I still think we were lucky that this guy stayed out in the open when we slowly circled around for better light and then were even joined by a third photographer.
The right angle of warm evening light and the overall golden hues of the still water of the lake with reflections of huge old Palms all came together to perfectly show off the jewel tones of the heron's breeding plumage.