October 2022 – Reflections of the Natural World

Our Wintering “White” Geese – Part I

By Jim Gain

Learn 100 Common Valley Birds is a photo blog series highlighting 100 of the most common Valley bird species.

Post #11 in the Learn 100 Common Valley Birds series. (Species 16 and 17/100.)

“Your first indication of their presence is the distant sound of baying hounds. As you look up, you see the sky flecked with tiny white moving shapes, which appear like snowflakes drifting lazily across the azure sky.” naturalist J. B. Grinnell

There are two species of “white” geese in California’s Central Valley. The Snow Goose is the larger and more widespread species compared to its cousin, the Ross’s Goose.

SNOW GEESE Anser caerulescens (Linnaeus, 1758)

INTRODUCTION

The Snow Goose is a Common Winter Visitor found primarily in the Central Valley.
Preferred habitats are fresh emergent wetlands, adjacent lacustrine waters, and nearby wet croplands, pastures, meadows, and grasslands. Common from November to early March, and fairly common in October and April in Central Valley south to Merced Co. Less common southward in interior.

DESCRIPTION

This medium-sized goose is distinguished by a blackish “grinning patch” or “smile.”

The adult white morph is completely white except for gray primary coverts and black primaries.

IMMATURES

The immature white morph is a darker, grayish and white mixed plumage.

DIMORPHIC FORMS

The species is dimorphic, consisting of light-morph (white) and dark-morph (blue) variations of Snow Geese. Until 1983, the 2 color morphs were considered separate species.

The adult blue morph has the same bill pattern, but its body is largely dark gray-brown except for white head and foreneck. White- and blue-morph birds interbreed and the offspring may be of either morph. These two colors of geese were once thought to be separate species; since they interbreed and are found together throughout their ranges, they are now considered two color phases of the same species.

IT’S IN THE GENES

The color phases are genetically controlled. The dark phase results from a single dominant gene and the white phase is homozygous recessive. When choosing a mate, young birds will most often select a mate that resembles their parents’ coloring. If the birds were hatched into a mixed pair, they will mate with either color phase.

DISTRIBUTION

Snow Geese adapted quickly to use agricultural fields, which is one reason their populations are doing so well. During winter and migration, look for them in plowed cornfields or wetlands. Also check lakes, ponds, and marshes where they roost and bathe along shorelines and in open water.

POPULATION EXPLOSION

The breeding population of lesser Snow Geese and Ross’s Geese exceeds 7 million birds, an increase of more than 300% since the mid-1970s. Since the late 1990s, efforts have been underway in the U.S. and Canada to reduce the North American population of lesser snow and Ross’s geese to sustainable levels due to the documented destruction of tundra habitat in Hudson Bay and other nesting areas. The Light Goose Conservation Order was established in 1997 and federally mandated in 1999. Increasing hunter bag limits, extending the length of hunting seasons, and adding new hunting methods have all been successfully implemented, but have not reduced the overall population of snow geese in North America.

NEXT POST – Our Wintering “White” Geese – Part II ROSS’S GEESE Anser rossii

Previous posts from the Learn 100 Common Valley Birds series:

Wood Duck

Aix sponsa

By Jim Gain

Learn 100 Common Valley Birds is a photo blog series highlighting the 100 most common Valley bird species.

Post #10 in the Learn 100 Common Valley Birds series. (Species 15/100.)

INTRODUCTION

The Wood Duck is arguably the most spectacularly beautiful duck in the Central Valley. It is a Fairly Common Year-round Resident throughout the wetlands and waterways of the valley. Similar to other dabbling ducks, the Wood Duck is an omnivore with a broad diet of seeds, fruits, and aquatic and terrestrial invertebrates.

APPEARANCE

Wood Ducks have a unique shape among ducks—a boxy, crested head, a thin neck, and a long, broad tail. In flight, they hold their head up high, sometimes bobbing it.

Like most waterfowl species, the wood duck is sexually dimorphic with the males sporting a glossy green head cut with white stripes, a chestnut breast and buffy sides.

Females are gray-brown with a white-speckled breast.

Female Wood Duck at Henderson Park, Merced County

DISTRIBUTION

Look for Wood Ducks in wooded swamps, marshes, streams, beaver ponds, and small lakes. They stick to wet areas with trees or extensive cattails.

NESTING

Wood Ducks nest in cavities in trees or in man made nest boxes and females may lay 9-14 eggs. The eggs are dull white to pale buff. Incubation is by female only, 25-35 days. Ducklings remain in the nest until the morning after hatching. Clinging with sharp claws and bracing with tails, young climb to the cavity entrance and jump to ground. Young are tended by females for 5-6 weeks, capable of flight at about 8-9 weeks.

WOOD DUCK BOXES

Wood Duck Nest Box at San Joaquin River NWR

As a cavity nester, Wood Ducks take readily to nest boxes.

Informative web pages by Ducks Unlimited:

FLIGHT CALLS

Wood Duck Flight Call by Ed Pandolfino

Previous posts from the Learn 100 Common Valley Birds series,

Killdeer

Charadrius vociferus

By Jim Gain

Learn 100 Common Valley Birds is a photo blog series highlighting the 100 most common Valley bird species.

Post #9 in the Learn 100 Common Valley Birds series. (Species 14/100.)

Status

The Killdeer is a Common Resident to California’s Central Valley. Killdeer belong to the plover family (Charadriidae) with 68 species worldwide. As their Latin specific epithet name indicates, they are quite noisy (vociferous).

Description

The Killdeer’s upperparts are mostly brown with white underparts. Their upper chest is interrupted by 2 black bands. The sexes are monomorphic (alike) and plumages are essentially identical throughout year.

Distribution

Killdeer can be found from Canada, south all the way to the coastal areas of Peru. In California’s Central Valley, Killdeer can be found in close proximity to humans, often in schoolyards, parks and businesses with dirt lots.

Nests and Young

Killdeer nests are located on mostly flat, gravelly open areas with little to no nesting material visible. They are also known to nest on flat graveled rooftops and parking lots. Killdeer young are precocial vs altricial at birth. A precocial bird is “capable of moving around on its own soon after hatching.” The word comes from the same Latin root as “precocious.” Altricial means “incapable of moving around on its own soon after hatchling.” It comes from a Latin root meaning “to nourish” a reference to the need for extensive parental care

Habits – Injury-Feigning Display

Performed by either sex, usually by only 1 member of pair at a time. If both members of pair are present, one usually gives alarm calls from a distance. In response to potential predator, bird crouches, head low, breast-bands minimally showing, wings drooping and partially extended, sometimes flapping to beat against the ground, tail fanned and dragging the ground to display rufous rump-patch. Displaying bird’s body is usually oriented away from potential predator, but its head is turned to the side such that the bird looks over its shoulder at potential predator.

Injury-feigning Display Creative Commons Image by Andy Reago & Chrissy McClarren

Similar Species

There is another breast-banded plover species similar to the Killdeer that can be found in the valley during spring and fall migration. The Semipalmated Plover has mostly the same coloration and marking except that it only has one band across its breast and it is a smaller species.

Check out the comparison between the two species below.

Previous posts from the Learn 100 Common Valley Birds series,

Northern Flicker

Colaptes auratus

By Jim Gain

Learn 100 Birds is a photo blog series highlighting 100 common bird species found in California’s Central Valley.

Post #8 in the Learn 100 Common Valley Birds series. (Species 13/100.)

Common Year-round Resident

Introduction

The Northern Flicker (Colaptes auratus) is a medium-sized bird of the woodpecker family. It is native to most of North America, parts of Central America, Cuba, and the Cayman Islands, and is one of the few woodpecker species that migrate.

According to the Audubon field guide, “flickers are the only woodpeckers that frequently feed on the ground”, probing with their beak, also sometimes catching insects in flight. Although they eat fruits, berries, seeds, and nuts, their primary food is insects. Ants alone can make up 45% of their diet. Flickers also eat berries and seeds, especially in winter, including poison oak, grape, and elderberries, as well as sunflower and thistle seeds. Flickers often break into underground ant colonies to get at the nutritious larvae there, hammering at the soil the way other woodpeckers drill into wood. One flicker’s stomach was found to contain more than 5,000 ants!

LEFT Male | RIGHT Female “Red-shafted” Northern Flicker

As well as eating ants, flickers exhibit a behavior known as anting, in which they use the formic acid from the ants to assist in preening, as it is useful in keeping them free of parasites.

Appearance

This brownish-gray woodpecker, larger than an American Robin, has a black-barred back and is spangled below with black polka-dots. Easily recognized as it springs into flight, the flicker flashes a large white rump patch and bright red-colored wing linings and tail feather shafts.

Distribution

The Northern Flicker is the most widespread woodpecker species in North America, found from the northern treeline south through the lower 48 U.S. states into Mexico, reaching into Central America as far south as northern Nicaragua. It is also found in Cuba.

Sub-Species and Intergrades

Ten subspecies of northern flicker are recognized with 4 sub-species in the “Yellow-shafted” form and the other 6 being in the “Red-shafted” form. At one time these two primary forms were considered two separate species called the yellow-shafted flicker (C. auratus) and the red-shafted flicker (C. cafer). But they commonly interbreed where their ranges overlap and are now considered one species by the American Ornithologists Union. The vast majority of Northern Flickers observed in the Central Valley are of the “Red-shafted” form.

“Yellow-shafted” Female Northern Flicker

COOL FACT – Tale of a Tongue

The tongues of most woodpeckers are adapted to spear and extract insects from wood, but the flicker’s tongue is a bit different — in ways advantageous for lapping up large numbers of ants.

All woodpeckers have an elongated tongue attached to an arrangement of bones, cartilage, and muscles known as the hyoid apparatus, which wraps around the bird’s skull, ending near the rear of its eye sockets. The Northern Flicker has an extra-long tongue that can extend up to two inches past the tip of its beak. It’s the perfect tool for probing into anthills. This lengthy tongue is supported by an elongated hyoid bone, which extends into the bird’s upper mandible.

*Northern Flicker by Ken Griffiths, Shutterstock*

Previous posts from the Learn 100 Common Valley Birds series,