Purple Sandpipers

Bird watchers will know this is on the level, even if others suspect hallucinations.

Purple Sandpipers

Purple Sandpipers really do winter on the shoreline of Halibut Point.

They forage at  the tideline, pulling tiny invertebrates from rocks and seaweed.

Are they really purple? Or is that a flight of fancy colored by intrepid, overly entitled observers at the winter shore? It depends on the angle of the light. The orange legs and bill make a nice complement to the plumage.

The Purple Sandpiper has the northernmost winter range of any shorebird on the East Coast. When the season mellows into spring they take off for nesting grounds in the high Arctic tundra.

They manage to grip near-vertical algae-slick rocks with sturdy feet and toenails.

When an especially large wave hits the rocks, the birds flutter up far enough to evade the incoming water.

Having worked out their remarkable adaptations and reflexes, Purple Sandpipers have a niche with few others at Halibut Point, and none so masterful.

Between tides they roost in sunny spots in the open. They keep one eye alert to danger but are surprisingly approachable.

Mallard Mixes

Duck genetics can get pretty mixed up, and so can nature lovers who try to make sense of what they see. Even though we're used to noticing Mallards in very specific patterns the reality is more complicated than that. Interbreeding among closely related groups is not unique to Mallards nor even just to ducks. It may or may not be a "conservative" occurrence, depending on perspective. Perhaps it "just is."

R to L: Mallard male, American Black Duck male, hybrid female

The Mallard is a common and widespread species in the large, fresh water duck genus Anas. Other species in this genus frequently commingle with Mallards, especially American Black Ducks. They're often seen together at Halibut Point. 

Northern Pintail (f) in foreground

This female Northern Pintail Anas acuta currently in residence at Halibut Point is fairly easy to distinguish from other Mallard-like ducks on the quarry pond. It has 'pure' Pintail characteristics of diminutive size, buffy-brown plumage, and gray legs and bill. But what about the bird to its rear in this picture, with the wing bars of a female Mallard but the drab olive bill of an American Black Duck? Its identity to ornithologists is more ambiguous. There's a blurring at least of the edges.

A typical female American Black Duck Anas rubripes

A typical female Mallard Anas platyrhynchos

A Gadwall female, until recently Anas strepera

Returning to the first photograph we can see that genes of a dark colored heavy-bodied male American Black Duck (center) seem to have influenced the appearance of the female duck standing on the left.

A Mallard x Gadwall x American Black Duck female hybrid?

Enlarging that photo we can take further stock of this bird's bill and plumage. It's possible that it exhibits Gadwall traits as well as Mallard and American Black Duck.

Mallard male

The male Mallard in the group is clearly characteristic of its species and gender.

A male Mallard x American Black Duck cross

Cross-breeding occurrences produce ambivalent plumages among male offspring too.

The hybrid male with a Mallard female

The drake in the photograph above blends American Black Duck and Mallard characteristics, at the expense of the iridescent green head. The female doesn't seem to mind, though it's a loss from our standpoint. Human aesthetics, and taxonomy, do not necessarily enter into matters of natural selection except insofar as they result in successful futures for the species.

Part of the concept of 'species' for both flora and fauna is that it preserves a stable group identity for its members. But as we've seen, birds in the Anas genus sometimes make inter-species pairings that produce viable offspring with mixed characteristics, especially when closely related species flock together.

Favoritism by humans has played a significant role in the increase of Mallards. According to local naturalist Chris Leahy, they "were once uncommon spring and fall migrants in New England. They only began to breed and to become common permanent residents when people began introducing feral or captive-bred  birds to private ponds and public parks. Their superabundance can cause problems for native waterfowl and even human health."

That puts humans in the Mallard mix too.

 

Mallard Chaperones

 

American Wigeon

At Halibut Point, almost any time you see a dabbling (surface-feeding) duck it either is, or is in the company of Mallards.

Ring-necked Duck, juvenile male

In part that may be because Mallards are more numerous than any other kind of duck, so they have a wing up on the prime habitat.

Green-winged Teal

But they're also not territorial nor competitive by nature. They make room for others.

Black Ducks, lower left

In the case of Black Ducks, Mallards commingle to the point of occasional inter-breeding.

Gadwall pair with Mallard pair

This can also be true of the closely related Gadwalls that stopped for a rest at the quarry this winter.

Female Pintail, foreground

Similarly this Pintail must have felt sufficiently reassured by the flock of Mallards to join them for a couple of days. Ordinarily it would frequent a pond with more vegetation than a deep water granite quarry.

The Pintail at the center of the Mallards

The fact that most of the singular 'guests' are females or juveniles gives further credence to the conclusion that Mallards are a reassuring presence for other ducks.

Juvenile Greater Scaup, in the water

Occasionally even diving ducks like this Scaup find the Mallard contingent companionable.

Female Common Merganser

A visiting Merganser found reassurance on the quarry pond by the escort of a Mallard drake.

Mallard Iridescence

Mallard Ducks, an everyday sight in public parks, look like nature exaggerated into artistic fantasy.

The males display a peacock-like iridescence about their heads. Both sexes show iridescent blue wing bars in flight.

Most of the Mallard's colorful effect comes from light reflected directly by feather pigments, as it does in a painting. Special brilliance results from light waves passing through iridescent structures, which are microscopic layers of crystals within the feather barbules. Their interspersion with air forms complex surfaces for refraction which, coupled with underlying pigments, create vibrant sheens on the feather.

Contrasted with the plumage array on its body, its yellow bill and orange feet, the male Mallard's iridescent green head makes a splendid sight in courtship and to casual Park visitors.

A couple of weeks ago as ice was beginning to form on the Halibut Point quarry, these Mallard Ducks swam by with the sunlight at a low oblique angle from the rear. Their apparently dark purple heads momentarily confused recognition. What happened to the lustrous green sheen?

Peter Brown, an art professor friend, supplied the answer. "Green light and violet light are complements. This means that when combined they will create white light. The microscopic structure of certain feathers refracts white light like a prism. At certain angles we see one color and as we shift our vantage point we will see the color’s complement. When one color is being absorbed by the feather, its complement is being reflected to our eyes. With iridescence this process flips back and forth."

This duck seems to be resting peacefully with a blend of green and violet iridescence.

Goldeneye Theaters

 

The quarry wall, Halibut Point

Water and ice have made dramatic cliff pictures (hydroglyphs ?) in the recent cycle of warm and cold weather.

Female Goldeneye

One day a bird normally found at Halibut Point only on the winter shoreline appeared at the base of the quarry's icy cliffs. It's the only time I've seen one on this interior pond.

The swimming hole

It found refuge in the small remaining area of open water that allowed it to fly in and out. Goldeneyes need less patter distance (running on the surface) than do Mallard Ducks for takeoff.

The duck diving, right center

The duck dove repeatedly in search of invertebrate food along the shallow edge.

Female and male Goldeneye pair at sea

When seen at close range it's obvious how these birds come to be named Goldeneyes.

Goldeneyes by coastal cliffs, Folly Cove

Their winter habitats can make as dramatic a sight for shoreline ramblers as the prime actors themselves.