My greatest excitement of the last two weeks was seeing a family of 20 COMMON MERGANSERS, a female and 19 juveniles! Yes, 19 babies!
I was shaking as I hurried to get these photos before the astonishing family quickly disappeared from sight. It was actually Steve Gerow who spotted the family foraging in the emergent vegetation just downstream of the Felker St.
Pedestrian Bridge. Even with all his experience, he was impressed with the size of this mother’s brood! He immediately did some research in Birds of North America and discovered that this species can sometimes be ‘conspecific nesters’, i.e. one female will lay her eggs in the nest of another member of her species. (A normal brood of Common Mergansers is about 10 but there have been reports as high as 17, so it is barely possible that it is one brood.)
Common Merganser babies, as well as the babies of Wood Ducks and Mallards, are ‘precocial’, meaning that they can forage for themselves as soon as they are born. This trait makes it possible for duck parents to have large broods without exhausting themselves in the process! In contrast, the nestlings of most songbirds require a much longer period of parental attention and therefore broods remain relatively small. It seems that precocity in birds was a great evolutionary achievement. I wonder if there is a downside? Anyway, what a gift to get to see such a large family. I hope they all survive. Steve surmises that they are nesting in some hollow cavity of a tree in the Tannery area, or perhaps further upstream.
After watching the merganser spectacle, Steve headed up towards the riparian area behind the Tannery just north of the Highway 1 Bridge. I tagged along. He found an astounding 35 different species – including a WOOD DUCK family and a PIED-BILLED GREBE family, each with about four young. I can’t tell you how happy I was to see the grebe family! After staring at that grebe nest last summer, hour after hour, I believe I have mysteriously taken grebeness into my soul. I get unreasonably happy when I see a grebe baby, as if there had been a birth in my own family. Here are photos of two of the juveniles, still sporting their harlequin colors.
Steve often hears a bird before he sees it. I was straining every ounce of brain power left to me to learn some of the songs that emerged enticingly from among the thick trees, trying especially to hear the ethereal song of the SWAINSON’S THRUSH as well as the bright, choppy warble of the BLACK-HEADED GROSBEAK. The latter is much easier than the former, but it was foreign to me until that day. I read recently that there is a European Bird called a Warbler Marsh who can mimic as many as 84 bird songs learned as the warbler migrates from Europe to Africa and back. What a musical accomplishment. I am struggling to even identify most songs, much less reproduce them! Is the Marsh Warbler the Mozart of the bird world? There is no Marsh Warbler in North America, but we have our own amazing version in the NORTHERN MOCKINGBIRD.
Among the less common birds that Steve heard first, and then saw, were NUTTALL’S AND DOWNY WOODPECKERS, PACIFIC SLOPE FLYCATCHER, WARBLING VIREO, OAK TITMOUSE, PYGMY NUTHATCH, WILSON’S WARBLER, and CEDAR WAXWING, all species that have been driven out of the former riparian woodland south of the Highway 1 Bridge , now denuded by development and levee construction. I dream of restoring some of that richness downstream, but it is probably impossible given the constraints imposed by the Army Corps of Engineers to protect the city against flood. We and the birds pay a terrible price for occupying the flood plain of a river. You can check the eBird website http://ebird.org/ebird/view/checklist?subID=S29839162 for the full list of Steve’s sightings.
Later last week, I walked up into the same area behind the Tannery and captured this mother WOOD DUCK out with one of her babies. I had never seen so clearly the brilliant metallic blue primary and secondary wing feathers (nor the green sheen on the cap) that the normally drab female Wood Duck displays during this breeding season. Isn’t it curious that Wood Ducks should concentrate their reproductive energies on their own brilliant plumage during breeding season, while the Pied-billed Grebes leave all that brilliance of color for their babies. Watching birds takes one deeper and deeper into a mysterious world.
I am reading a fascinating book on crows by John Marzluff called Gifts of the Crow, How Perception, Emotion, and Thought Allow Smart Birds to Behave Like Humans. 2012. As a result, I am paying more attention to these highly intelligent and adaptive urban residents. It turns out that juvenile AMERICAN CROWS have bright yellow skin color at the sides of their beaks, designed to help the adult aim the food into the gaping jaw of the young with maximum efficiency. Not surprisingly, this skin patch is called a ‘gape’. I took the following photos just south of the Felker St. Bridge on the east side of the river. The behavior of the crows seemed extremely human to me!
Another highlight of the last two weeks was getting a chance to go on a group hike along the San Lorenzo River at Henry Cowell State Park with the legendary local naturalist Fred McPherson. Fred has spent decades studying the natural history of the San Lorenzo River Valley and is well known in the valley for his advocacy work, his teaching and his outreach to children. He produced a beautiful DVD on the San Lorenzo River which I purchased and plan to watch when despair about our vanishing wilderness overwhelms me. It is available at the gift shop at Henry Cowell.
I feel so much gratitude for people like Steve and Fred who have devoted their lives to learning about nature and teaching the rest of us. A special shout-out also to Carol Carson, who fled Texas for Santa Cruz, and who has spent her last seven years enthusiastically organizing many such nature walks in the San Lorenzo Valley.
Have a wild week, Jane!