The new year has brought me the good fortune of finding and photographing four of the most elusive and endangered bird species found in the S.F. Bay area: the Least Bittern; American Bittern; California Clapper Rail; and, Burrowing Owl. Like most birders in this area, I had never seen the Least Bittern and rarely seen the others.
The California Clapper Rail is a Federally and State listed endangered species (meaning it is in immediate danger of becoming extinct) primarily because of loss of wetlands. Similarly, Burrowing Owl numbers have declined steadily since the 1940’s because of habitat loss through urban development and are listed as a Species of Special Concern in California. In addition to habitat loss, non-native predators (domestic and feral cats, Norway rats, Red fox) also present threats.
Observing any one of these four birds in the wild is rare not only because of limited populations but because the appearance of these birds (their plumage) and their behavior is so well adapted to their habitat that they are difficult to find.
Both the Least Bittern and American Bittern are secretive and solitary birds that spend their lives in marshes, moving very slowly, often times remaining motionless amongst tall, dense vegetation such as reeds and cattails. However, when prey such as fish, frogs or crustaceans get close, these birds will strike very quickly. Unlike most other herons which will flush when disturbed or threatened, the Bittern will freeze –typically with it’s neck stretched skyward. In fact, sometimes they will even slowly sway in this position to resemble the surrounding waving reeds.
Burrowing Owls have a unique symbiotic relationship with ground squirrels. The two animals don’t share burrows but rather, the owls take over vacated burrows for their nest. And yes, they actually do dig to expand their burrows. In exchange, the ground squirrels benefit by having another set of wary eyes looking out for mutual predators. Burrowing owls are also unusual, as owls go, as they are active during the day and at night (diurnal). For more info on these owls and their preservation, check out the following link to the Burrowing Owl Conservation Network (http://burrowingowlconservation.org/index.html).
The California Clapper Rail is another furtive bird that is best seen during periods of plus high tides in the winter months when it is flushed out of its dense saltwater/ freshwater marsh vegetation habitat. This is a medium-sized bird (13-19 inches long and about 8 to 14 oz) with a narrow body (“skinny as a rail”) and a conspicuous whitish tail. They are well adapted to moving through marsh vegetation quickly; rarely fly but can swim short distances well. Although the Clapper Rail can conceal itself very effectively, it will often give away it’s presence with an unmistakable loud clattering call.
As recently as 40 years ago, about 5,000 Clapper Rails were located in the S.F. Bay estuary but today, that number is estimated in the1,000-1,800 range. Again, habitat destruction and non-native predators are primary causes. Clapper Rails spend most their time feeding on small fish, snails, marine worms, mussels, crayfish, crabs and bugs found in shallow waters along tidal channels and mudflat edges.
Click this link to see a gallery of images of these elusive and endangered birds. /new-photos/elusive-endangered/
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Also included in the photo gallery are images of a Merlin. Merlins and Kestrels are both small sized Falcons with the Merlin being a bit larger of the two. I have seen Kestrels fairly often but only twice have I spotted a Merlin. So, it has been an elusive bird species for me. The Merlin diet consists primarily of other birds that it attacks and captures mid-air.
And finally, I’ve also included photos of the White-faced Ibis. The WF Ibis is a medium-sized wading bird (it stands approx. 2’ tall with a 3’ wingspan) with a long, slender downcurved bill and fairly dark plumage that on closer inspection has an iridescent sheen of bronze, purple/red and green (although winter plumage is somewhat duller). In California, this bird is most often seen in the central valley during the winter months but occasionally a few isolated birds find themselves visiting the S.F. Bay. This individual bird was found foraging at Palo Alto’s Baylands Nature Preserve. Interestingly, I saw a WF Ibis in this same location last year at this same time.