Ducks stop traffic

"Traffic on the busy freeway ground to a near halt as one or more momma ducks tried to get their brood safely across the 10-lane freeway, towards the adjacent Los Angeles River."

Overthinking it

On Saturday, I took part in an exciting discovery at Placerita Canyon. My fellow-birder and I were able to ID, based on its unique cat-like mewing call, a California Gnatcatcher. The bird list I got from the nature center there indicates it as a rare winter visitor to that park, recorded before only in 1972 and 1999. 

         

This morning, I am going over a photo that I took yesterday. Because the photo is taken from directly below it, all I can really make out was the plain underside, and a little bit of the head, showing a light supercilium. Very little is visible of the wings, and its back is completely hidden.

I can tell it is a sparrow, but which one? I sift and scan through pictures and drawings of various native species in books and websites. White-crowned sparrow? Chipping sparrow? Clearly not, no indication of the stripes on the crown, plus, wrong beak coloration. Song sparrow? Lincoln sparrow? No, no streaking on the chest. Savannah sparrow? No, no yellow visible. Brewer's sparrow? Possibly, but the facial markings would be different ... I groan and complain loudly to no one in particular how hard this bird is to identify. I even go so far as to send out the photos to some birder friends asking for help.

Hearing my vexation, my six-year old strolls up from behind, takes one look at the picture on the computer screen, and says, "Dad, isn't that just a regular [house] sparrow?"

Oh.

He's right, of course.

Augury

Image from http://birdsandclimate.audubon.org/

The augur was a priest and official in the classical world, especially ancient Rome and Etruria. His main role was to interpret the will of the gods by studying the flight of birds: whether they are flying in groups or alone, what noises they make as they fly, direction of flight and what kind of birds they are. This was known as "taking the auspices." The ceremony and function of the augur was central to any major undertaking in Roman society—public or private—including matters of war, commerce, and religion.   (from Wikipedia)

The NYTimes today carries an excellent op-ed piece by Brian Kimberling that advocates paying serious attention to todays augurs. He points at the following finding by Audubon about the connection between bird movements and climate change, based on a review of its annual Christmas Bird Counts over the last forty years (see also the image above for a visual illustration of this fact):

Nearly 60% of the 305 species found in North America in winter are on the move, shifting their ranges northward by an average of 35 miles. Audubon scientists analyzed 40 years of citizen-science Christmas Bird Count data — and their findings provide new and powerful evidence that global warming is having a serious impact on natural systems. Northward movement was detected among species of every type, including more than 70 percent of highly adaptable forest and feeder birds.

The Wikipedia article on "Augur" notes that an augur "does not predict what course of action should be taken, but through his augury he finds signs on whether or not a course already decided upon meets with divine sanction and should proceed." The signs we are getting from the birds adds weight to the growing consensus that the course we humans have been following must be changed.

(The author of that NYTimes piece Brian Kimberling has a new book out called "Snapper", apparently a collection of fictional stories about an ornithologist who studies the connection between bird migration and climate change. I look forward to reading it.)

Big Day

Female Western Bluebird at Malibu Creek, March 16, 2013

I spent Saturday with two friends, doing a thrilling "Big Day". We went to beaches, camp grounds, parks, wildlife reserves, lakes, creeks, and rivers all over L.A. county, at Malibu, San Fernando Valley, Playa del Rey, South Bay, Long Beach, trying to find and identify as many birds as we could.

The first time I had done this was in December with another birder.  I had seen 84 different birds that day, but it left me feeling that I could have done better, given we had faced a combination of starting late, limited daylight hours, heavy traffic, and poor planning. I therefore set myself a target to see a 100 birds this time. To make the day more enjoyable (and yes, to increase my chances to meeting that target), I invited a couple of  birder friends I've met several times and gotten to know over the past year at various Audubon walks and trips.

We planned quite carefully in advance, with many excited emails sent back and forth a few days before. We discussed and argued about alternative locations. We solicited inputs from other birders we know. We took into account factors including the times of first light, sunrise, sunset and last-light, and poured over tide charts. We examined our own old birding records and read through online reports of birds sighted in our planned locations on eBird.

 

Clockwise from top left: Western Gull, Snow Egret, Oak Titmouse, Whimbrel

All this preparation paid off beautifully. Over a span of about twelve hours, covering around 80 miles of ground in driving between sites, we identified a total of 119 species** of birds, including two I had never seen before (see the full list). The day began a little before sunrise at Malibu Lagoon, and ended in L.A. river a little after sunset. One of the first birds we identified was a song-sparrow trilling just before day-break. My last view in the fading light was of an indescribably beautiful gathering of hundreds of Black-necked Stilts.

Glaucous-winged Gull at Malibu Lagoon

Inter alia, we saw three different types of Loons (Common, Pacific, Red-throated), a Glaucous-winged Gull, Caspian and Royal Terns at Malibu Lagoon, a Chipping Sparrow at Malibu Creek, a Eurasian Wigeon pair (a life bird for me) and two Cackling Geese at Reseda Park, an early Bullock's Oriole at Lake Balboa, a gorgeous male Wood Duck at Sepulveda Basin Wildlife Reserve, Elegant and Royal Terns at Playa del Rey beach, three pairs of hooded Mergansers at Ballona Freshwater Marsh, Canvasback and several Ring-necked ducks at Alondra Park, and a Blue-winged Teal pair at L.A. River - Willow Street.

Chipping Sparrow at Malibu Creek

Because I wanted to focus on identifying birds, and because my lens's autofocus broke half-way through the day, I don't have a lot of photos to show. Luckily, one of my companions took a great set of photos as well.

There were also some remarkable "easy" misses: Northern Flicker, Downy Woodpecker, American Kestrel, Northern Harrier, some of which we thought we might have seen but couldn't confirm because we didn't get a sufficiently good look. On the drive back, mulling this over, we concluded that with more experience and skill we might well have added another dozen birds to our list. For next time...

** Update: Three days later, we were able to resolve one of the photos we took that we weren't sure about to be of a Sharp-Shinned Hawk, not Cooper's (one of the notoriously hard identification problems in North American birding). This brings our total from the day to 120!

Curb your cat

Cat eyeing a bird, Phoenix, Arizona.

The following is from the abstract of a recent study in Nature Communications, titled "The impact of free-ranging domestic cats on wildlife of the United States" by Loss, Will, and Marra:

Here we conduct a systematic review and quantitatively estimate mortality caused by cats in the United States. We estimate that free-ranging domestic cats kill 1.4–3.7 billion birds and 6.9–20.7 billion mammals annually. Un-owned cats, as opposed to owned pets, cause the majority of this mortality. Our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals. Scientifically sound conservation and policy intervention is needed to reduce this impact.

Many of the news reports have emphasized only the total counts of birds killed. I was curious to find out which particular birds are affected and  how much. I found an interesting table in the supplement to their paper, listing the birds affected in order of proportion of mortality estimated to be caused by cat predation. It addresses the very question I had. The following is a piece of it:

Why I can't be an Ornithologist

Savannah Sparrow, Playa Del Rey

I came across a news article on Wired today  discussing a new research finding that the neural pathway for songbirds hearing birdsong is very similar to that of humans enjoying music.

Delighted, I sought and found the original article by researchers from Emory University. The abstract reads:

Since the time of Darwin, biologists have wondered whether birdsong and music may serve similar purposes or have the same evolutionary precursors. Most attempts to compare song with music have focused on the qualities of the sounds themselves, such as melody and rhythm. Song is a signal, however, and as such its meaning is tied inextricably to the response of the receiver. Imaging studies in humans have revealed that hearing music induces neural responses in the mesolimbic reward pathway. In this study, we tested whether the homologous pathway responds in songbirds exposed to conspecific song. We played male song to laboratory-housed white-throated sparrows, and immunolabeled the immediate early gene product Egr-1 in each region of the reward pathway that has a clear or putative homologue in humans. We found that the responses, and how well they mirrored those of humans listening to music, depended on sex and endocrine state. In females with breeding-typical plasma levels of estradiol, all of the regions of the mesolimbic reward pathway that respond to music in humans responded to song.  In males, we saw responses in the amygdala but not the nucleus accumbens – similar to the pattern reported in humans listening to unpleasant music. The shared responses in the evolutionarily ancient mesolimbic reward system suggest that birdsong and music engage the same neuroaffective mechanisms in the intended listeners.

So, specifically, they've found that the reaction to male birdsong differs by gender. The females find it musical, while the males find it cacophonous.

I was interested in more details. I started reading the full text of the paper... until I came across this sentence, describing the methodology of the experiments:

"Sixty min following the onset of the stimulus presentation, birds were deeply anaesthetized with isoflurane and decapitated."

Evolving Security

Image taken from the LA Times Article

According to an article in the LA Times today, Australian scientists have made a fascinating finding, that the Superb Fairy-Wren has evolved a security counter-measure to foil brood parasites: while still inside the eggs, they learn from their mother a secret catch-phrase (unique to each nest!) that they can use to request food. The mother only feeds in response to this particular vocalization.

The original article appears in Current Biology.