World Migratory Bird Day 2018

International Migratory Bird Day

In 1993, the Smithsonian Migratory Bird Center created International Migratory Bird Day (IMBD). This educational campaign focused on the Western Hemisphere and celebrates its 25th year in 2018. Since 2007, IMBD has been coordinated by Environment for the Americas (EFTA), a non-profit organization that strives to connect people to bird conservation.

Broad-winged Hawk Juvenile

Broad-winged Hawk juvenile at Marin Headlands Hawkwatch during fall migration

In 2018, EFTA joins the Convention on Migratory Species (CMS) and the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) to create a single, global bird conservation education campaign, World Migratory Bird Day (WMBD). WMBC celebrates and brings attention to one of the most important and spectacular events in the Americas – bird migration.

Important Bird Areas

Over the years, EFTA has made changes and improvements to International Migratory Bird Day. They developed the concept of a single conservation theme to help highlight one topic that is important to migratory bird conservation. Over the years, these educational campaigns have been integrated into numerous programs and events, focusing on topics including the habitats birds need to survive, birds and the ecosystem services they provide, the impacts of climate change on birds, and the laws, acts, and conventions that protect birds, such as the Migratory Bird Treaty Act, the Endangered Species Act, and the Convention on Biodiversity.

Pectoral Sandpiper

The Pectoral Sandpiper migrates from South America to the Arctic, a total return-trip of more than 30,000 km

They also removed a specific date from the event. Once celebrated only on the second Saturday in May, they recognize that migratory birds leave and arrive at breeding and non-breeding states at different times, depending on many factors. They also stop at different sites across the Western Hemisphere to rest and refuel, providing opportunities to engage the public in learning about birds and their conservation. Today, they maintain traditional event dates on the second Saturday in May and the second Saturday in October, while encouraging organizations and groups to host their activities when migratory birds are present.

Nashville Warbler

Nashville Warbler

Join us for a bird walk at Battle Creek State Wildlife Area and celebrate World Migratory Bird Day with Wintu Audubon!

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Tree Swallows Return, It Must Be Spring

Tree Swallow Male

Whenever I see Tree Swallows (Tachycineta bicolor) I know that Spring is upon us. I have witnessed small groups of these gorgeous aerial acrobats twice, from an excellent vantage point, engage in what seems to be a courtship or pair bonding display. (Click on photos for full sized images)

Here you see, what appears to be an adult male clinging to a snag, being approached by a yearling female sporting the mostly brown plumage with a hint of greenish-blue.

This activity seems to be centered around the small hole in the snag which the male has been checking out, but is obviously too small for a nesting cavity.

Tree Swallow

The male assumes a rather vertical posture and the female comes toward him, both with mouths open

Tree Swallow

This is another encounter where it is difficult to determine the sex of these two birds but I believe the bird on the right is a female

Tree Swallow

They may make several passes at each other with their mouths open like this

Tree Swallow

And then actually connect with a mock feeding display

Tree Swallow

Of course this all takes place in the blink of an eye so I never really saw this mouth to mouth connection until I viewed these photos from the Sacramento National Wildlife Refuge blind I took a few years ago.

I concluded that this must be pair bonding behavior, after all, Spring is in the air!  Does anyone know for sure?

Here is another photo of this beautiful species.

Tree Swallow

Watching the Tree Swallow, or most any swallow, makes me wish I could fly myself, how about you?

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It’s Parenting Season

Black-headed Grosbeak Male

Black-headed Grosbeak Male

It’s spring, and the busier the birds and bees are, the better it is for all of us. Part of that busy-ness has to be raising offspring.

Birds take on rearing their children with all the variety and flair of feathers. Many young birds are brought up in two-parent nests; others just by mom, some just by dad; some are raised by foster parents; still others are grouped into “it takes a village” scenarios. There are numerous child-rearing styles. But no young bird prospers without substantial parenting in some form.

Black-headed Grosbeak Male Feeding Young

Black-headed Grosbeak Male Feeding Young

Billions of aspiring avian moms and dads are in this child-raising season right now. Most songbird pairs share their nesting duties. Typically, the female incubates and turns the eggs, and quietly chirps to the young, who learn her voice before they hatch. Males in some species spell their mates on the nest, but more often do guard duty, dive-bombing or distracting predators. Both parents feed the hatchlings, hunting down hundreds of insects and making scores of feeding visits to the nest every day. When the fledglings take wing, the male often shepherds them, while mom perhaps begins a second or even third nest.

Black-headed Grosbeak Female

Black-headed Grosbeak Female

Black-headed grosbeaks, colorful, big-billed birds, take the sharing of nest duties a notch or two farther than most species. When a dangerous jay or neighborhood cat approaches, the female readily joins her mate in harassing the predator, attempting to drive it from their vulnerable young. On his part, the male, with rare egalitarianism, undertakes an even share of egg incubation and nestling-warming. More noisily than his mate, he nests with what seems foolhardy flair; he sings loudly right from the nest, as if he can’t contain his proud papa-hood.

Black-headed Grosbeak Juvenile

Black-headed Grosbeak Juvenile

Unike the precocial ready-to-go chicks of turkeys, ducks and quail, hatchling grosbeaks are altricial—blind, naked, and helpless. Within two weeks, however, under their parents’ relentless feeding and guardianship, the babies are full grown and feathered, ready to try their wings.

Like so many of our nesting birds, grosbeaks are travelers, wintering in Mexico and nesting as far north as British Columbia. Like robins, they have adapted effectively to suburbs and parks. They prefer to nest near water where both trees and brush offer cover. The females weave loose nests, usually on outer branches no higher than a second story window. Both the male and female sing profusely, a tune and tone frequently likened to that of a tipsy robin. His song is especially loud and clear, waltzing through the woods any time of day.

These singers of the American West dine on seeds, insects, and fruit, happily foraging high above us mere walklings. They are, however, happy to descend to our level to empty our feeders of sunflower seeds. There we can enjoy their burnt orange plumage and oddly hefty bills.

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Anna’s, Rufous and Calliope: Hummingbirds of the West

Calliope Hummingbird Male

Here in Northern California I am fortunate to have at least three of the western hummingbirds of North America visiting my yard. The least common species of hummingbird I see here is the Calliope Hummingbird (Stellula calliope)(click on photos for full sized images).

Calliope Hummingbird Male

The smallest of the North American hummingbirds at just 3 1/4 inches, and with wings extending beyond its short tail, the Calliope Hummingbird is usually distinguishable from its larger counterparts by size alone. This is a photo of a male Calliope Hummingbird on the feeder next to the much larger male Anna’s Hummingbird.

Calliope Hummingbird and Anna's Hummingbird Male

Because of its shorter wing length, the Calliope also has faster wingbeats, making it sound more like a bumble bee. This also sets it apart from the larger hummers.

The male also has a unique gorget among North American hummingbirds. His iridescent gorget is divided into separate magenta-red rays, which can be elevated in an elegant star-burst display against the white background of his throat. This photo by Wally Rufous is the best photo I have ever seen of this phenomenon!

Calliope Hummingbird Male

Calliope Hummingbird Male Courtship Display courtesy Wally Rufous

This beauty is the female Calliope Hummingbird, she looks similar to the female Rufous Hummingbird (Selasphorus rufus) but she has dark and pale spots in front of her eye and a weak pale line over the base of her bill. She is the latest of our local breeders, not nesting usually until mid-May.

Calliope Hummingbird Female

The female Rufous Hummingbird has more rufous in her flanks and often has a few patchy orange-red feathers on her throat. She will begin breeding in April.

Rufous Hummingbird Female

The male is the only hummingbird in North America with a rufous back.

Rufous Hummingbird Male

He also sports a brilliant orange-red gorget.

Rufous Hummingbird Male

Enjoy this close-up look at this guy preening.

The most common hummingbird seen in my neck of the woods is Anna’s Hummingbird (Calypte anna). The male is the only North American hummer with both a rose red crown and gorget.

Anna's Hummingbird Male

The female is the earliest breeder of all these species, arriving on breeding grounds shortly after the males in November. Here you can see the female collecting nesting material.

Anna's Hummingbird Female

The ability to take advantage of both nectar and insects allows Anna’s Hummingbirds to avoid competition from other hummingbirds by nesting in the winter. This is a photo of the female Anna’s Hummingbird in her nest.

Anna's Hummingbird Female on Nest

The male Anna’s can be heard for quite a long way when performing his courtship display known as the “dive display” discussed in one of my previous posts.

Anna's Hummingbird Male

If you haven’t seen a hover of hummingbirds around a feeder before, you may want to watch this video I filmed off my back porch. These little “jewels of the sky” are a blast to watch!

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Eggs Came First

Western Bluebird Hatchlings

Western Bluebirds

Eggs came first. There. Now you know. Eggs were around long before there were chickens, or any birds at all.

Egg-laying dominates the history of vertebrates, who appear in the fossil record in FARMB order: Fish, Amphibians, Reptiles, Mammals, and Birds. Of them all, only mammals regularly practice live birth. The other classes all lay eggs, and seeming exceptions of live birth are usually illusions—the mother actually makes eggs, but she retains them in her body until they hatch, and then delivers her wrigglers to the outside world.

That little evolutionary trick can be quite useful. Here in California, for instance, the southern alligator lizard lays eggs. The northern alligator lizard, however, keeps her eggs inside. This allows her to move them to warm spots throughout the day, spurring their development. Where the warm season is short, that accelerated development can mean the difference between the young growing up enough to endure the coming winter or perishing quickly.

Birds, of course, have a premium on light weight, so retaining eggs in their bodies is not a good option. Indeed, in the service of minimal mass, most female birds develop only their left ovary, and even that shrinks to a speck outside the breeding season. During nesting season, however, that ovary is full and busy, typically producing an egg a day several days in a row—what chickens have been bred to do year-round.

EGGS

Initial bird development is similar to that of humans. The ovary releases a protein-rich ovum which can then be fertilized.

But at that point, where humans will feed their young placentally, birds must prepare a self-sustaining egg. The ovum gathers its golden protein-rich yolk, which in turn is joined by albumen, the egg white. The albumen consists of water and more protein for the developing chick. Uterine cells squirt that eggy blob with calcium carbonate, which hardens into the smooth shell that curves round the birds’ precious hope of life. Egg farmers know that sufficient calcium in the mother’s diet is vital to forming viable eggs. Where calcium is lacking, a mother bird may donate up to 10% of the eggshell from her own bones.

With the egg formed, other cells squirt the species’ pigmentation onto its surface. Only two pigments, a blue-green and a red-brown, create all the variety of patterns and colors on birds’ eggs.

American Robin Nestlings

American Robin Nestlings

Like reptiles, who often bury their eggs, birds that nest in cavities and burrows usually have white eggshells. More exposed eggs are often speckled into camouflage. But some, like robin’s baby blues, are strikingly uncamouflaged even though exposed to the world and its predators. This presents another chicken-and-egg question: Which came first, the parenting or the color? Can protective parents like robins simply afford colorful eggs because they are dutifully present to shield their young, or did colorful eggs come first, with their demand for attentive parents? Does care, then, create beauty, or does need evoke care in successful species?

Killdeer Eggs

Other questions abound. Some eggs are oval, even round; others are conical. The hypothesis that conical eggs roll in a circle, and therefore are more likely among cliff-dwelling birds, isn’t really supported by the evidence. Another hypothesis is that since round eggs require less calcium to coat them, while pointier eggs can pack more tightly for incubation, the two shapes offer competing advantages; or perhaps it’s just that birds with more streamlined bodies can more readily lay thinner, pointier eggs.

Northern Mockingbird Nest

Northern Mockingbird Nest

This time of year, the most numerous bird on Earth, the domestic chicken, supplies the goods for more questions that many of us enjoy: How did you dye your eggs? Where did you find that one? What’s for breakfast? Or the worthy observation: aren’t eggs amazing and beautiful!

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