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.

Iridescence of a Hummingbird

Costa's Hummingbird, taken at Indian Wells today, Oct 28, 2012

I have never seen this species of hummingbird before. I chanced upon it in the grounds of the hotel where I was staying this weekend. It is a desert bird, named after a French ornithologist. Like all hummingbirds, the male has a spectacular metallic sheen to the feathers in its head and gorget. 

Why do they look so cool? 

The following is taken from asknature.org: 

"To summarize, hummingbird iridescence is due to interference colors produced by a stack of about three films whose optical thickness is one-half the peak wave length. Each film is a mosaic of platelets of elliptical form. Each platelet is about 2.5 microns long and one micron wide. The platelets are not homogeneous and consist of air bubbles encased in a matrix of refractive index about two." (Greenewalt et al. 1960:253)

Greenewalt CH; Brandt W; Friel DD. 1960. The iridescent colors of hummingbird feathers. Proceedings of the American Philosophical Society. 104: 249-253. 

Seeking for that bird

(Say's Phoebe at Madrona Marsh, Oct 14, 2012)

I came across these beautiful lines in an essay by Robert Louis Stevenson, The Lantern Bearers:

"There is one fable that touches very near the quick of life: the fable of the monk who passed into the woods, heard a bird break into song, hearkened for a trill or two, and found himself on his return a stranger at his convent gates; for he had been absent fifty years, and of all his comrades there survived but one to recognise him. It is not only in the woods that this enchanter carols, though perhaps he is native there. He sings in the most doleful places. The miser hears him and chuckles, and the days are moments... All life that is not merely mechanical is spun out of two strands: seeking for that bird and hearing him. And it is just this that makes life so hard to value, and the delight of each so incommunicable."

Urban owl

Exciting night! I was just about to sleep when I heard a western screech owl just outside the bedroom window! Much to the amazement of the bird expert who alerted me to it, it had been recently spotted in our neighborhood just this past month by another birder.

What makes this is so unusual is that these owls normally live only in the woods up in the mountains in L.A., away from people and urban areas. You can see this clearly in the map of reported sightings that I captured from ebird.org; my report from last night is the lonely one in orange near Beverly Hills. Blue reports are older; the one closest to it in blue dates back to 1949! The expert had said "I suppose it is a dispersing hatch-year bird looking for a place to settle in."

I didn't get a good look at the bird, but got to see it fly out of the tree it was in (outside my immediate neighbor's backdoor). Having never seen one before, I was surprised to see it was quite small, only about 8 inches or so.

Oh, and I could record its soft calls that are comprised of a rapid series of "bouncing ball" whistles: https://www.youtube.com/watch?v=-aoXS_C5SbA&feature=plcp