Black Skimmer - Rhynchops niger

These photos from Florida trip in February, Fred Howard Park, Tarpon Springs. I think they show a male Skimmer, because of the gap in the bill. The deep black suggests alternate plumage. The frontal shot show the laterally compressed bill, which enables it to slice through the water with minimal resistance. 

Side view shows the long wings (span 44") and short red-orange legs, and of course that amazing underbite:

Last shot gives us a closer look at the bill. Skimmers fly very close to the water, dipping the lower mandible into the water's surface and snapping it shut when they contact a fish. Fun to watch.

Skimmers are seen on both coasts. In California their northern range limit is the SF Bay Area. Once year we had one loafing at Shorebird Marsh in Corte Madera, Marin County. They are seen regularly at preserves in the south bay, and are known to breed there.

The Black Skimmer, Rhynchops niger, displays great size differences between male and female, with the larger male fully 10% bigger or more in all measurements, and fully 30% heavier (365 gm. vs 265 gm., or 12.9 oz. vs 9.3 oz.). The male has a bowed or "open" bill (BNA account).

Skimmer taxonomy tends to vary with the source, and remains unresolved. What follows is the mostly widely accepted understanding, and to me the most sensible.

Order: Charadriiformes - Huge and diverse order, including shorebirds, gulls, auks, etc.

Family: Laridae - Gulls, Terns, and Skimmers. (Skuas and Jaegers now have their own family)

Subfamily: Rhynchopinae - The Skimmers. Only one genus here. The other sub-families in Laridae are Larinae (Gulls and Kittiwakes) and Sterninae (Terns and Noddies). Skimmers thought to be closer to the terns, but really not very close.

Genus: Rhynchops - Skimmers. 3 species world-wide. Other two are the African Skimmer (yellow tip on bill, and not dimorphic) and the  Indian Skimmer (always with white collar, and orange-yellow on bill).

Species: Rhyncops niger - Black Skimmer. 3 subspecies, all in the New World. Ours in North America is the nominate subspecies, R. n. niger, which is mostly coastal, but seen inland in Florida and California (especially at the Salton Sea). Subspecies further south are more riverine in their nesting and foraging.

Skimmer population in NA is fairly stable, but nesting success in not high (less than 50%), with disruption by flooding, predation and human disturbance. Caution advised in banding or observing nesting colonies (duh). 

Barrow's Goldeneye

At Lake Solano Park (just below where Pleasant's Valley Rd. joins Route 128), the viewing is usually good for a good variety of river ducks, and on Feb. 5 we spotted many Common Goldeneyes and a few Barrow's, both male and female, foraging in mid-stream opposite the picnic area.

The male Barrow's Goldeneye is unmistakeable, with a large white crescent on the face plus other clear diagnostic marks. The female Goldeneyes can present more of a challenge. The Barrow's female's bill is usually all orange, shorter than that of the Common Goldeneye, and "deeper" at the base, giving the bill a stubby appearance. The Common's longer bill has a different shape, which I'm still trying to get used to. When viewing a group of 3 ducks (above) at 25-30 yards, we could easily discern that one was an adult male Barrow's, and a second was an adult female Barrow's. We kind of assumed that the other female Goldeneye, with orange mainly at the distal part of the bill, must be a Common Goldeneye female. On returning home I checked the photos, and began to wonder about the puzzling female with the half orange bill, whether it was a Common or Barrow's female.

Photo 2 shows the Barrow's male with the puzzling female:

Photos 3 below shows Barrow's male and female swimming together. Of note there were Common Goldeneyes pretty close by, although these 3 keep pretty much to themselves. There were no significant courtship displays taking place.

Don't know what to make of the fact that the male's iris is the typical bright yellow, or almost yellow-orange, whereas the iris of the females here has a greenish cast to the yellow.

The guide books are somewhat limited in what they can teach about differentiating similar looking species, so I needed more information. Sibley provided just what was needed in this article from his website: http://www.sibleyguides.com/2010/01/distinguishing-female-barrows-and-common-goldeneyes/

After reviewing Sibley's article on the Sibley Guides website, I realize that such ID challenges are far from straightforward. It seems one pretty much has to disregard head shape for clues, at least regarding birds that are actively feeding, which is often the case with the Goldeneyes I see. The feathers of the head are lowered before a dive, so the profile dramatically changes and the steep forehead disappears. Same thing happens with Eared Grebes, which can have the profile of a Horned Grebe when foraging, i.e. the "steep forehead" becomes shallow, and the forward peak on the crown is lost.

Here's a very unscientific collage of some of my female Goldeneye photos, with those from Lake Solano at the top:

Top left is a typical Barrow's female, with an all orange bill that is thick at the base and a bit "stubby". The bill features a gentle curve of the lower mandible that make it almost look up-turned. The next 2 shots in the top row are of the puzzling female shown earlier above, showing what I think is a more stubby (shorter) bill than seen on the Common Goldeneyes in the row below. In the top row note the gentle curve of the lower edge of the bill, the deep/thick base, and more extensive orange than we see on the Common GE's bill. In all 3 shots we see a pretty good black "nail" at the tip of the bill.

The bottom row in the composite shows 3 female Common Goldeneyes. Note the relatively straight line along the bottom of the bill from base to tip, which can vary a bit depending on the angle of view. The orange at the tip is confined to the distal 1/3 of the bill, and the border is a clean diagonal line. The bill seems less deep at the base, seems relatively longer (less stubby), and has a small black nail at the tip. Note the great variation in head shapes among the 6 photos. Common Goldeneye females can indeed show more orange in the bill, but rarely, especially on the west coast.

Bottom line is that the consensus of "Barrow's" for the puzzling female seems to be a reasonable ID. For me the lesson is to focus on the bill. Weigh other features like head shape only if a careful comparative study can be made of birds in similar postures, such as Sibley did in Oakland some years ago. Likely he was at favorite spot for Barrow's, where Lake Merritt flows out though Laney College (area currently being restored), where the birds could be studied at close quarters.

Another lesson perhaps is to beware of any given selection of photos that are meant to prove a point, as selection bias severely limits any conclusions that can be drawn.

Reddish Egret - Egretta rufescens

Experienced birders know that you not only have to go to the "right" places to find certain birds, but you have to go at the right time. For the Reddish Egret that means going to areas that have broad open tidal flats, and going at low tide, as Reddish Egret hunts for small fish in shallow (2-6") water. Well, during our visit the low tides were rather high, i.e. high lows, and we saw just one Reddish Egret, and only briefly at that. The good news was that the bird was close and the light was good.

The plumage of the adult dark morph Reddish Egret changes little with breeding season, which can be vary in timing. The most dramatic changes are in the bare parts, as shown in the first photo. The legs become blue, the base of the bill becomes brighter pink with a jet black tip, and the lores blaze with stunning blues and violets. It doesn't get much better. Add to that the varied and sometimes frenetic foraging behavior, and you've got a memorable sighting.

Second photo was taken when the bird got too close (30'), and shows the spread wings often seen when its hunting, along with some of the fine plumes of the back and the impressive shaggy neck feathers.

A reflected image of the subject can add interest to a photo, or not, but this is the first time for me where the reflection was more in the nature of a shadow, which I thought was pretty cool. The bird is back-lit in all 3 photos.

The Reddish Egret population, decimated by the plume hunters, has made a decent recovery in most areas. It is pretty strictly a coastal species, and prefers warm salt water. Eagles can be a significant predator of both chicks and adults, and that may mean trouble in Florida where the Bald Eagles are successfully breeding in greater numbers. Raccoons can also disturb nesting colonies, and fire ants add to the threats.

Reddish Egret in seen in Florida, the Gulf Coast states, Baja, both coasts of Mexico, and further south on tidal flats of Costa Rica, Belize, various West Indies islands, and even the north coast of Venezuela. 

Population:

"As an inhabitant almost exclusively of coastal lagoons of the Gulf Coast states, the Reddish Egret is North America’s rarest and least known ardeid. This species was nearly extirpated from the United States by plume hunters prior to 1900. Since then, populations have recovered, and U.S. populations currently total about 2,000 pairs; less is known about numbers in Mexico or the Caribbean." (BNA Online, #633, Lowther and Richard, 2002)

On color change in bare parts:

http://www.saaudubon.org/articles/SoftPartColoration.html

Ring-necked Duck - Aythya collaris

This year we've been fortunate to view greater than average numbers of Ring-necked Ducks,Aythya collaris. At Las Gallinas in November we watched a raft of up to 100 Ring-necks, swimming and foraging as a pretty close group, but seemingly not paired up. Similarly, in early December at the Sacramento NWR we counted a flock of over 400 unpaired Ring-necks in the pond near the viewing platform. Since then numbers have declined at both locations, for whatever reason(s). Perhaps the drought has played a role, but water levels seemed about the same at these managed areas.

Fast forward to January 30, where we watched a few Ring-necked ducks on Jan 30, close to the viewing platform on the auto route at Sac NWR. The pair shown here appeared to have formed a bond, as they rested quietly.

Pair formation in Anatidae, the Duck Family, is variable. The Geese and Swans are known to mate for life, whereas most the the usual duck species we see here (dabbling and diving ducks) are seasonally monogamous, forming the pair bond on the wintering grounds or during migration. The Ring-necked Ducks are thought to form pairs during migration, which for them means March and April, as they head to subarctic breeding areas across Canada and the the northern U. S.  Perhaps this paired were simply hanging out as birds of a feather, rather than a bonded pair, but they did not drift apart in the period we watched.

Good article on waterfowl breeding:http://www.ducks.org/conservation/waterfowl-biology/waterfowl-mating-systems/

Overcast afternoon light is usually bad for birds with bright coloration or complex plumage, but it works nicely for species that have a lot of black and white. 

The identification of the male Ring-necked Duck is pretty straightforward if you can see the bill, with the prominent white outline where the bill joins the face. When the bill is tucked it's still pretty straightforward, as there are only 2 diving ducks (Aythya species) with black backs, and the grayflank with the upward white spur at the shoulder is distinctive for the Ring-necked male. The uncommon Tufted Duck, Aythya fuligula, is the other black-backed diving duck, but the male has a bright white flank and a less prominent spur at the shoulder. So when viewing a large flock of diving ducks, say at an area like Lake Merritt in Oakland, check for ducks with black backs, and then check their flanks to see if gray or white.

Here's a shot of a Tufted Ducks taken at Aquatic Park, Berkeley about 6 years ago.

Note the very white flank and the lack of a white ring on the bill. Oh, and the tuft!

And here's one from Lake Merritt, Oakland. Can't see the tuft well, but note the white flank and the lack of a white ring on the bill.

White-faced Ibis - Plegadis chihi

The Central Valley is a great place to view wintering White-faced Ibises, although you're never quite sure where you'll run into them. They forage in agricultural lands, flooded fields, and a variety of wetlands and fresh-water marshes. The White-faced Ibis is similar to the Glossy Ibis of the Gulf Coast, but the 2 species don't often hybridize, even when on the same breeding grounds. They feed on a variety of animal prey, ranging from small insects and earthworms up through crustaceans, snails and even small fish.

While at the Colusa National Wildlife Refuge this past Wednesday, Patti and I were lucky to watch a lone White-faced Ibis foraging directly in front of the viewing platform. Dull afternoon light was not the most flattering for photos, but we got great looks of the bird probing deeply with its sensitive bill, feeling for prey items on the bottom of the pond or in the mud. The shots barely hint at the beautiful iridescent colors one might see in better light.

We watched the White-faced Ibis feeding actively for over 20 minutes. It likely found and consumed some aquatic insects during that period, and it eventually came up with what looked like a crayfish, which it promptly swallowed.

Thought it might be worth taking a video to show the active probing methods it used, similar to those of the longer-billed shorebirds. The videos were shot through the scope using my regular camera, the Nikon V1.

Longer video (15 sec.):http://youtu.be/dRuRy3ob1I0

Shorter video (6 sec.):http://youtu.be/QUhqoYHbYFI

Lincoln's Sparrow - Melospiza lincolnii

Patti and I just returned from a 3 day birding trip in the Sacramento Valley, including Lake Solano and the refuges. The last bird I photographed, at Lake Solano (Putah Creek) was found by Patti, who waved excitedly and pointed urgently to a bush along the river bank. A sparrow was perched there, rather backlit, but a quick look suggested a Lincoln's Sparrow. I snapped one quick shot and it flew off, as Lincoln's Sparrows tend to drop out of sight with annoying speed. A quick look at the photo was a bit disappointing (underexposed), but it appeared that some detail could be coaxed out of the shadows, or so I hoped.

The shot was sharp enough to attempt a photoshop rescue, which I did on returning home, using LightRoom 4.0. Mainly I used adjustments for lighting and contrast, and I was pleased with the result below. Lincoln's Sparrows often pop us just briefly, preferring to forage in a area with good cover. I never had a chance to fire off a second shot.

We were pleased that the "enhanced" version confirmed our field ID. Note the buffy eye ring (you may have to enlarge the photo), slightly buffy malar stripes, fine streaking in the throat, and nicely streaked breast with a central spot like the Song Sparrow, and the white belly.

Lincoln's Sparrow, Melospiza lincolnii, is one of the 3 Melospiza sparrows that are seen in the U.S., along with the ubiquitous Song Sparrow and the less commonly seen Swamp Sparrow.

Green Heron

The water treatment ponds at Las Gallinas (San Rafeal) host a rich variety of birds. On a recent trip there a Green Heron provided some close looks as he foraged intently along the rocky shoreline of pond #3.

Too close for a full frame shot.

Green Heron, Butorides virescens, is seen regularly at these ponds, often located by following a flying bird to note where it lands. Once they land they don't move very much, as they watch intently for prey, usually staring at the water. Their neck is kept flexed, ready to extend in a sudden strike. Distance here was about 20', too close for a full frame photo of this 18" bird.

Note the black cap, rich chestnut on the side of the head and neck, and the precise white edging of feathers of the wing (coverts). Their posture is a bit like that of a Night-crowned Heron, The Green Heron will not be mistaken for any other species. 

The the Green Heron extends his neck to get a better view of potential prey

The Green Heron is part of a complex once called the Green-backed Heron, then conidered a single species, but since split into 2-3 species, including the dark endemic Galapagos (Lava) Heron, B sundevalli, and the widely distributed Striated (Mangrove) Heron, B. striata.

While I watched the Green Heron succeeded several time in catching minnows, and once was able to get two fish with a single strike!

The last shot is my favorite, as he turned to look about to see if anyone had admired his prowess, giving me a good look at the eye and lore area.