Friday, November 29, 2013

Review: The Crossley ID Guide/Britain & Ireland


Richard Crossley and Dominic Couzens have published a new guide to the birds of Britain and Ireland. This book adheres to the Crossley system of bird identification in which plates are crammed with dozens of bird photographs. The birds in these photos come in different sizes (ranging from adequate to frustratingly tiny) and postures, all against busy habitat scenes. Ascertaining the relative sizes of the species is difficult. Sample plates can be viewed at the Amazon site links in this post.
Crossley’s hypothesis is that we learn to identify birds by knowing size, shape, behavior, probability, and color patterns. You don’t get this synthesis in a normal field guide. Crossely writes, “repetition and familiarity are the best tools for learning any subject.” He believes that traditional portraits with arrows indicating salient field marks are not the most effective educational tool. Nevertheless, the guide begins with 12 pages with small photographs of single birds, often with up to three dozen species per page. Although small range maps accompany each plate, the book lacks a detailed map of Great Britain. The text accompanying the plates is short and in very small font.

So how did you learn to identify birds? While I was in the seventh grade, my two brothers and I competitively quizzed each other with a stack of 5 x7 cards with Agassiz bird portraits on them. I think these cards were from the Audubon Society. That year my teacher, John Trott, initiated a year-long bird identification unit in conjunction with his banding birds. Much of my birding involved peer learning. If I were learning birds today, undoubtedly I would be using the Thayer Birding Softwarequizzes and attending birding field trips.

Although I own Crossley’s earlier book on eastern birds (see link below), when I need a field guide, I first turn to my Sibleyguide. But Crossley claims his book is not aimed at me, but, rather beginning and intermediate birders. His goal is to teach neophytes. I would love to know if he has evidence that his system is better than traditional field guides. 

Wednesday, November 27, 2013

Black-throated Sparrow


Black-throated Sparrows breed across much of the western United States and Mexico. Northern populations migrate south in the winter. The species can be common and consumes insects in the breeding season, and grass seeds, and, while breeding, also a variety of arthropods. Populations in the United States may be declining with thr growth of urban areas and the clearing of mesquite lands for agriculture (Handbook of Birds of the World Alive). I took this photo along I-10 in New Mexico.

Monday, November 25, 2013

Black Walnut

Last week, Erika and I found these Black Walnut fruits on a tree in the Carleton College Arboretum. Black Walnuts are found across eastern North America. Black Walnuts have been widely introduced elsewhere in North America and Europe. The nuts are often expensive, but offer "a gourmet touch to cookies, breads, and cakes” (UMN Extension). This source gives instructions for the harvest, curing, and storage of Black Walnuts. Nuts are harvested by hand from wild trees, mostly from Missouri. The fruits in this photo are past their optimal harvesting stage.

Black Walnuts are large, long-lived deciduous trees. Fruiting begins when the tree is about five years old—the tree may live about 130 years.  The tree produces high-quality wood. The shells are used as an ingredient in abrasive cleaners, cosmetics, oil well drilling, and water filtration (Wikipedia).

Saturday, November 23, 2013

Ginkgo

Readers can find a plethora of information on the Ginkgo on the WEB. This tree has been used medicinally for thousands of years and is now one of the top-selling items American herbal remedy stores (Mayo Clinic); they are also eaten as food. But be careful gentle reader, the Mayo Clinic lists only two or three diseases, out of nearly 100 claims of efficacy, that ginkgo has been firmly and scientifically proven to alleviate. Even these few ailments are not prevented, like some types of dementia and pain from clogged leg arteries. These diseases are perhaps equally well-treated by conventional medicines. Note that various Ginkgo tissues can be poisonous, depending on the dose and the part of the tree from which the herbal medicines are derived. The seeds are poisonous, but, as an enzyme in the seeds speeds up alcohol metabolism, were traditionally served with alcoholic drinks in Japan (Encyclopedia.com). People can also suffer various and potentially serious allergic reactions to Ginkgo. 
But the Ginkgo’s pharmacological potential is not what interests me most. Last week I was surprised to find a female Ginkgo at the Minnesota Landscape Arboretum. Females are not often planted because their fruit is messy and smells like rancid butter or vomit. Most Ginkgo trees you see in city parks are males, which can be propagated by grafting or grown from shoots. Look for these magnificent trees along major city boulevards.

The Ginkgo is a “living fossil.” Until one was discovered in 1690 in a Japanese temple garden, European botanists knew the tree only from 270-year-old fossils. Because of its high status in Buddhism and Confucianism, the tree was widely planted in Japan and Korea. Trees in those countries now found in the wild are so genetically uniform that they are generally believed to have escaped from cultivation (Wikipedia). 

Some temple trees are thought to be over 1500 years old. Ginko trees survived the bombing of Hiroshima and some of those trees live today. The tree has now been cultivated around the world and has been grown in the United States for the past 200 years. Nevertheless, in our country, the Ginkgo does not grow in the wild (Wikipedia).

Note the parallel veins in the leaf in the photograph below (taken several years ago at the Landscape Arboretum—the same tree, in fact, as in the first photo). Such venation is typical of primitive plants, as is the single split in the central part of the leaf. Their reproductive cycle is also primitive. Their exact relationship to other plants is uncertain, but may be most closely related to seed ferns (Wikipedia). They have no close living relatives.

Thursday, November 21, 2013

Great Blue Heron

I found this Great Blue Heron in almost the only open water I encountered on 19 November 2013. Air temperatures were slightly below freezing and most of the local lakes sported a thin coat of ice. (The relatively warm weather of the last two days has transformed the lakes back to a liquid state, but the bitter cold predicted for the weekend should reverse the ice-free trend.)

When they are cold, herons droop their wings to absorb warmth from the sun (although this bird stood in the shade); they also avoid wind by seeking shelter, in this case behind a steep riverbank. Note that the heron is standing on one leg, keeping the other tucked up under its ruffled feathers. Presumably the heron is also using a counter-current exchange in the wet leg. This system exchanges the warmth of arterial blood with the cold venous blood coming from the lower foot. The result is that most of the bird’s heat is retained near the body rather than lost to the cold water.

Stragglers are known to attempt to winter in Minnesota, but most Great Blue Herons winter south of the state. The spots on the wing coverts and the solid-gray crown indicate this bird is in its first year. This heron did not appear to be wounded or sick (although it walked away rather than flying).

Tuesday, November 19, 2013

Jabiru

Jabirus breed from southern Mexico to southern Bolivia, northeastern Argentina and Uruguay. This stork is abundant only in the Chaco Pentanal of Brazil, Paraguay and Argentina, otherwise this bird is considered to be a threatened species. I took this photo at Yarinacocha in Amazonian Peru on 26 July 1972 and, despite my years in Peru and Ecuador, I have never seen one since.

A few vagrants have been reported from south Texas and one from Tulsa, Oklahoma. I think these records should be accepted with caution—perhaps as few as 250 Jabiru survive in Central America (Handbook of Bird of the World—Alive; AOU Checklist). More likely the Texas birds are escaped from captivity, as Jabiru are occasionally kept in zoos.

A number of reasons exist for the decline of the Jabiru. Typically they nest on the crowns of tall palm trees. The nests are made of sticks and mud, which are added to each year. Note the large stick being carried by the Jabiru in my photo. Eventually either the palm is killed or the nests, getting to be 2 meters wide and 1 meter deep, fall. Adults also often desert their nests, which are also attacked by Crested Caracaras. The species is also vulnerable to habitat destruction and hunting. The fat young are a popular food item in the Amazon Basin (Handbook of Bird of the World—Alive).

Jabiru eat almost any small animal they can catch, including fish, frogs, crabs, snakes, insects, turtles, and even young caimans (which are subdued by the Jabiru beating them against logs). Fish are often herded by groups of Jabirus into shallow water. Jabiru are not adverse to stealing food items from other storks or ibis (Handbook of Bird of the World—Alive).

Sunday, November 17, 2013

Mountain Caracara

While Crested Caracaras are the only caracaras found in the United States, other species inhabit South America. Mountain Caracaras are found in the Andes from southern Ecuador to central Chile. I took this photo high in the Peruvian Andes.

Although these large, atypical falcons are strong fliers, they feed on the ground, scratching and stomping to disturb arthropods, rodents or birds. They also feed, often with vultures, upon carrion and human garbage. They build unsubstantial nests on cliffs, while others build larger nests on electric towers (Handbook of Birds of the World—Alive).

Friday, November 15, 2013

Crested Caracara

Crested Caracaras are found from southern Texas and southern Arizona to northern South America. An isolated population also breeds in central Florida. The first photo was one of my first (taken almost 50 years ago!), a caracara in eastern Mexico. The orange spot in the middle of its breast is probably its naked, extended crop. I photographed the second bird a couple of years ago in the Rio Grande Valley of Texas.

Caracaras are opportunistic feeders that specialize in carrion. They often feed in flocks and with vultures. They are classified as falcons but are often mistakenly thought to be vultures or hawks. Locally known as Mexican Buzzards, in Mexico they are sometimes called “Quebrantahuesos,” which I translate as Bone-breakers. They enjoy carrion but also search for whatever invertebrates or vertebrates they can find. The name caracara is thought to be derived from “traro-traro,” a Native American word mimicking one of the caracara’s calls. The Aztecs were inspired to build their city Tenochtitlan (now Mexico City) by a caracara eating a snake while perched on a cactus. This legend is depicted on the Mexican flag and on their coat of arms (Morrison and Dwyer 2012).

Wednesday, November 13, 2013

Pileated Woodpecker

Banding a Pileated Woodpecker, like this female caught last week, is often a noisy, bloody affair as the bird drills holes in the bander’s hands (see gif on a previous post). This woodpecker is a “keystone species” in forest ecosystems (Bull and Jackson 2011). The holes excavated in trees by this species are used by many birds and mammals for shelter and nesting (Boreal Owl, Wood Duck, martens). Furthermore, Pileated Woodpecker workings decompose and recycle forest logs. Because their deit consists of carpenter and other wood-eating ants and beetles, forest trees are protected from attack by these arthropods.

Monday, November 11, 2013

Brown Creeper

Brown Creepers breed from Alaska, and southern Canada, south to the northern United States and through the Rocky Mountains to Mexico and Central America. They winter across much of North America. Here in the southern half of Minnesota, they are often abundant migrants and common winter residents. Elsewhere, populations have declined as mature forests are logged and dead trees cleared.

We banded this creeper among a flock of Ruby-crowned and Golden-crowned kinglets. This photo is one of the few in this blog that is heavily photoshopped (to erase my hand from the picture, but leaving the bird mysteriously floating in space). My goal here was to show you how this often-considered to be drab bird is actually quite elegant. When they are abundant in our back woods and as they furtively creep up forest tree trunks, Erika often calls these brownish birds "tree lice." But look closely at the checkered wing patches and the rusty rump!

Small birds like creepers and kinglets often struggle to maintain their body heat during frigid Minnesota winters. During cold spells, creepers roost in tree cavities and often roost in tight masses of 20 or more individuals behind loose pieces of tree bark (Paul and Bernice Noll).

Saturday, November 9, 2013

Giant Water Bug

I was surprised to find this Giant Water Bug trucking across the Carleton College Arboretum. They are common across the northern United States and Canada. They are among our largest bugs and are active all year. They normally live under water. In the fall, these bugs fly about looking for deeper waters where they continue hunting their prey under the winter ice. Often they are attracted by lighted areas at night as the bugs are moving to suitable ponds and rivers.

They eat a variety of invertebrates and tadpoles, salamanders, small fish and even birds (eduwebs). Their larger prey is caught by their powerful front claws and subdued by enzymes injected to the prey’s body. Their bite is painful, but they are otherwise harmless to people.

Thursday, November 7, 2013

Eastern Bluebird

Eastern Bluebirds, like this young bird Erika and I saw in the Carleton College Arboretum, are always pleasant to find. Previously, I posted a few times on this species—try the search box to the right side of this blog.  Recently I published posts about Western and Mountain bluebirds.

All three species of bluebirds are known to hybridize, albeit infrequently. Genetic studies indicate that Eastern and Western bluebirds diverged in the late Pliocene, some 2.45 million years ago (Gowaty and Plissner 1998, Power and Lombardo 1996). These studies also conclude that bluebirds, although definitely thrushes, are not closely related to other members of the thrush family.

Tuesday, November 5, 2013

Greater Yellowlegs

On Saturday, 2 November 2013, I saw a large shorebird feeding in a riffle in the Cannon River. My first thought was “Willet,” but soon I observed yellow legs. The leg color, the large size, and long, somewhat up-curved bill add up to Greater Yellowlegs.
Elphick and Tibbitts (1998) list a wide variety of wetland habitats for the Greater Yellowlegs. Although these authors include slow-flowing streams, this yellowlegs’ river was slightly beyond slow-moving. Up to its belly in water, the yellowlegs moved quickly, occasionally feeding like an egret, plunging its bill, head, and neck into the river. Both yellowlegs consume invertebrates, but, unlike Lesser Yellowlegs, Greaters also eat small fish.

Sunday, November 3, 2013

Golden-crowned Kinglet

At the end of October, we banded a few small, mixed-species flocks of kinglets and creepers. We caught a couple of dozen birds. All but one of the kinglets, both Ruby-crowned and Golden-crowned, were male. In the fall, male Ruby-crowned Kinglets migrate later than their females, thus the lack of females this year is somewhat perplexing. This Golden-crowned Kinglet is a male—note the orange feathers at the back and under the center of the crown.

Golden-crowned Kinglets breed further south and winter further north than Ruby-crowneds. Golden-crowneds, however, are hardier and migrate later than Ruby-crowneds. Wintering birds here in Minnesota can withstand nighttime temperatures below −40 degrees C. In such conditions, small groups of kinglets may huddle together to keep warm (Swanson et al. 2012).

DNA studies indicate that kinglets are closely related to titmice and Old World warblers. Golden-crowned Kinglets are closely related to European Goldcrests. Ruby-crowned Kinglets, on the other hand, are only distantly related to Golden-crowned Kinglets (Swanson et al. 2012).

Friday, November 1, 2013

New Zealand Fantail

New Zealand Fantails are Old World Flycatchers that occur in two morphs, a pied morph such as in this photograph, and one that is black. Erika and I photographed this fantail in 1990 at Arthur’s Pass in New Zealand’s South Island.  Here 75 to 88% of the birds are pied. On New Zealand’s North Island, 99% of the birds are pied. This bird’s buffy eye stripe indicates that it is young.

New Zealand Fantails are widespread and occur in both native habitats and in parks, farmland, and pine plantations. They eat arthropods, most often flycatching, and occasionally seeds. Often they follow other birds, and also feed near livestock or humans. These small, tail-swishing birds are threatened by introduced species such as cats, possums, and mynas—furthermore they are often roadkill (Handbook of Birds of the World—Alive).