Eurasian Tree Sparrow

Yesterday, Gerald Hoekstra and I drove to a bird feeder south of Hastings in nearby Dakota County, Minnesota. For the last few days, an Eurasian Tree Sparrow was reported from that location. Gerry and I spent over an hour trying to spy the bird among a plethora of House Sparrows at the feeder. We finally noted its chestnut crown (not gray like the House Sparrow’s) and black ear patches. After seeing it a few times, we also recognized the Eurasian Tree Sparrow by the bird's slightly smaller size and paler overall coloration.

The weather—a frigid -5 degrees F., with wind chill warnings posted—did not help finding the bird or taking decent photographs. We had permission by the landowners to watch from the road, but not to enter their property. This was decent of them, but did not allow us an opportunity for closeups. Also not helpful were a flock of Blue Jays that bullied the sparrows from the feeders. These photos are our best effort, the top one by me, and the bottom two digiscoped by Gerry, who very kindly gave me permission to post them here. (The last photo is of the bird in flight, bounding from the feeders to either the ground or to a nearby bush.)

Eurasian Tree Sparrows were introduced to North America from Germany in April 1870. They were released in an effort to "enhance the native North American avidfauna" in Lafayette Park, in St. Louis, Missouri. This initial introduction may have been augmented by subsequent releases. The sparrows rapidly became established in St. Louis, but House Sparrows outcompeted them in the countryside. Eurasian Tree Sparrows slowly spread into Illinois and Iowa—the main breeding range now encompasses about 250 kms from north to south.

This expansion more or less follows the Mississippi River. The species prefers wooded city parks and woodlots. A quick look at eBird illustrates their range and various extralimital sightings. Birds have been sighted around the northern midwest, and as far afield as British Columbia, Oregon, and the East Coast. Ornithologist do not know if these distant sightings are of escaped cage birds, sparrows arriving by ship from Europe or Asia, or individuals originating from their expected range in North America.

The source for most of the information and the quote in this post is Barlow and Leckie (2000). Not included in their account in The Birds of North America is a specimen from Huron, South Dakota, of an Eurasian Tree Sparrow collected on 19 April 2005 by a Purple Martin enthusiast clearing his bird houses of House Sparrows.

Ferruginous Hawk

The mostly white underparts, dark leg feathering extending to the toes, and pale head, all indicate that this raptor is a Ferruginous Hawk. This individual perched on a high-tension pole near Pierre, South Dakota; the photo was taken several years ago.

Ferruginous Hawks are found dry grasslands in the northern Great Plains and adjacent Canadian prairie provinces, and western Washington south to northern Arizona and New Mexico. They winter in the American Southwest and northern Mexico. Their primary prey consists of rabbits, ground squirrels and prairie dogs. The hawks’ numbers fluctuate with their prey.

Ornithologists are uncertain about how well Ferruginous Hawks are faring. Populations appear to be declining in several regions, but there are few data and even fewer hypotheses for the causes. Numbers have definitely declined in some ares of the Canadian prairie provinces and in North Dakota (where they are now absent). More southern populations seem to be holding steady. Some western populations are increasing, while others, in northern Utah and eastern Nevada are decreasing (Bechard and Schmutz 1995).

Swallow Tanager

The third in my tanager series of photographs from my youth is this Swallow Tanager from Limoncocha, Ecuador, taken on 28 June 1976. Regular readers of my blog may correctly guess that this photo is one of a series taken of captive birds in a holding box.

This tanager is so strange that, until recently, it was considered to be in a family of its own, the Tersinidae. Unlike tanagers, this species has a broad, swallow-like bill, long wings, and it nests in holes rather than making uncovered nests. Molecular studies, however, place Swallow Tanagers firmly within the tanagers in the family Thraupidae.

Although the birds are usually at least seasonally common, Ornithologists do not know much about the distribution of Swallow Tanagers across the Amazon Basin and northern South America. Scientists are not clear as to the degree of migration, if any at all, exhibited by this bird.  Some populations may be residents, others short-distance migrants, while still others may be nomadic. Erika and I have records of Swallow Tanagers from eastern Peru in the Andean foothills (Tingo Maria) on 19 June 1972, 14 October 1972, and 1, 2 and 7 December 1972. SwallowTanagers are found forest clearings, coffee plantations, and in canopy tree tops. They consume fruits and arthropods (Handbook of Birds—Alive!).

Review: The Warbler Guide App

This amazing app is available at the iTunes Store for $12.99 for iPhones and iPads, and it is worth every penny. (An Android version is coming.) If you make this purchase, be sure you are buying the app and not the book with the same name (unless, of course, you want both formats). 

Some people say, “There is nothing new on this Earth,” but they have never seen The Warbler Guide App. This app is a fast, intuitive way to identify the warblers of the United States and Canada by visuals and/or song. You can quickly access images of all species with comparisons to similar warblers.  Side, face, underside, and head-on views are all available. Similar species are shown on the bottom of the screen.

You can filter the images by region of North America, color, and season. You can even fill in, almost like "painting by numbers," the colors of the parts of the bird you’ve seen, and the app will give you identification suggestions. You can combine this with a description of the song—is it buzzy, clear, or what?  Does the song descend or go up?  The result is that you are presented with just a few of the most likely warblers based on your description.

The app contains a library of songs, with multiple variations for each species. You can set the songs to play at half speed, which may help you to learn them. (The songs’ pitches do not seem to be affected.)

What sets this app apart from anything else I have seen is its 3-D images. You can view a bird portrait and rotate it anyway you want—sideways, upside down (good for under-tail coverts), straight-on, or fleeing.  You can get both close-up and far-way views. You can pick two similar species and rotate them simultaneously.  It’s worth the $12.99 just to see this one feature alone!

The app contains all the information found in The Warbler Guide book, which I have previously recommended in this blog. Range maps, habitat, and behavior of each species are easily accessed. The birds can be arranged by general color, alphabetically, or taxonomically.

You have to see this app—welcome to the new world of field guides….

Hepatic Tanager

The second tanager among my old photographs was this Hepatic Tanager, seen at my aunt’s ranch near El Galpon in northwestern Argentina. The date was 27 July 1965. I listed Hepatic Tanagers again in Big Bend National Park on 17 July 1966, and many times in Peru in 1972 and 1973.

I took a double-take when I looked at this photo after all these years. It seems way too red on the head, compared in Hepatic Tanagers in the United States. Our birds have much more dusky ear coverts. A review of Eddleman (2002) reveals that, what we now call Hepatic Tanagers, may actually be three species. The Hepatic Tanager inhabits North and Central America, the Tooth-billed Tanager is found from Costa Rica to Bolivia, and the Red Tanager, like the one in my photograph, encountered in open areas of the Amazon Basin to northern Argentina. (Handbook of Birds—Alive! recognizes these three species, calling them Northern Hepatic, Highland Hepatic, and Lowland Hepatic tanagers.)

Tanager taxonomy is further confused at the genus level. Molecular work indicates that Hepatic Tanagers are closely related to Western and Flame-colored Tanagers, and less so to Summer or Scarlet Tanagers. Furthermore, the genus to which Hepatic Tanagers belong, Piranga, appears to be more closely related to grosbeaks than they are to other tanagers (Handbook of Birds—Alive!).

Blue-gray Tanager

Recently I discovered photographs of three South American tanagers in my digital files. This first is a Blue-gray Tanager, found in northern South America, north into Mexico. In July 1965, my father sent my brother and me to visit our recently widowed Argentine aunt. We had spent the previous year earning half the trip’s fare. I was 18, my brother 16—we’d both been birding perhaps three years. I took photos during the journey, but with only a 300 mm lens, few of the images are worth sharing. Time has also not been kind to the Kodachrome.

This Blue-gray tanager visited a papaya slice on our balcony in the city of Belem, Brazil. This bird was not a lifer—we boys had already listed it in Trinidad a few days earlier. Blue-gray Tanagers are often found in non-forested habitats, including city parks and gardens and, in fact, thrives in human-altered areas (Handbook of Birds—Alive!). They are known to nest in crevices in buildings.

This tanager’s diet includes fruits, nectar, and arthropods. They are often found in pairs, mixed-species flocks, and loosely associated groups of other Blue-gray Tanagers. This individual appears to be the nominate race, Thraupis episcopus episcopus, found in the Guianas and eastern Brazil, and first described by Linnaeus in 1766. The species is widespread and abundant across its range.

Band-tailed Pigeon

In the United States, Band-tailed Pigeons occur in two, non-overlapping areas. These populations are considered to be racially distinct, with one occurring from southern British Columbia through California. The other is found from Utah and Colorado south into Mexico. Banding studies show that some individuals trespass between these two ranges (Keppie and  Braun 2000). Other races occur from Mexico into South America. This photo, taken several years ago, is of a dove in the treetops above the Nisqually National Wildlife Refuge.

Band-tailed Pigions have a long nesting season—up to three nests per year—but most clutches have but one egg. Nestlings are “fed curd-like crop milk” produced by both parents. These doves descend from their foothill forests to devour wild and domestic fruits and grains (Keppie and  Braun 2000). Hunting greatly reduced Band-tailed Pigeon numbers in the early 1900s. Hunting still occurs, but this pressure no longer appears to be affecting overall population size. Nevertheless, Breeding Bird Surveys indicate this dove is "decreasing at an average annual rate of 2.8% across its North American range" (Keppie and  Braun 2000).

Carolina Wren

Except for posting a photo, I find I have not blogged much about Carolina Wrens. The species is abundant in the American southeast and in parts of eastern Mexico. Here in the upper midwest, this wren is casual throughout the year. I have heard its ringing “tea-kettle, tea-kettle” call once in Minnesota and I seen it a few times in South Dakota. Swanson (in Birds of South Dakota), suspects that most records in that state are the result of post-breeding dispersal by young birds from southern breeding areas.

Perhaps due to warming climate, Carolina Wrens have expanded their range north since the late 1800s. These wrens, however, do not survive cold winters. They do quickly recover from winter setbacks, as they often nest up to three times during the summer, and nests with four or five eggs are the rule (Haggerty and Morton 2014).

This photo appears to be a February 2011 shot taken at the Corkscrew Audubon Sanctuary in Florida.

Rough-legged Hawk

Large size, black belly, white base to the tail, all indicate that this photo is of a Rough-legged Hawk. Also note the dark underwing splotches on the flying bird’s wrists. John Holden and I encountered this individual in the Burnsville (Dakota Co.) landfill on 10 December 2014. We immediately knew the hawk’s identity because of its hunting habit of hovering above the wastelands surrounding the dump. Rough-legs can be completely black to very pale—I have posted photos of a much paler individual in an earlier post in this blog.

Like the Northern Shrike, Rough-legged Hawks breed across the arctic of both northern hemispheres. In North America, they winter to the southern United States (though they are less frequently observed in the southeast). They consume lemmings, voles, ground squirrels and birds. Breeding and wintering populations fluctuate in response to density of prey populations. Ornithologists do not know if, once in a wintering area, Rough-legged Hawks stay at one location or nomadically search for new areas with abundant prey (Bechard and Swem 2002).

Northern Shrike

John Holden and I took this photo just west of Northfield on 10 December 2014. Gray, foggy days are not really conducive for digital photography. Furthermore, birds perched on telephone wires do not usually produce very aesthetic compositions. But freezing fog combined with the wires to make this photograph of a Northern Shrike slightly more interesting than I predicted.

Elsewhere I have blogged about identifying Northern and Loggerhead shrikes. The thin black mask that does not traverse the fore-crown indicates this bird is a Northern Shrike. The bill is not as stubby as a Loggerhead's. Especially in the winter, Northern Shrikes consume many small birds and mammals, which they impale on barbed-wire, thorns, and in tree branch forks. Due to their razor-sharp bills, Northern Shrikes are one bird that I do not like to band.

Northern Shrikes are found across the Arctic areas of the Northern Hemisphere. Birds in Europe and Asia, where they are named Great Grey Shrikes, are found further south than are North American ones. Our Northern Shrikes typically move erratically in the winter only to the Central United States.

Northern Shrike systematics are murky. Within North America, ornithologists question if eastern and western races exist. Northern and Great Grey shrikes used to be treated as separate species. In any given sample of Old and New World birds, you can identify about 75% of the birds as to their origin. Does this fact indicate we are dealing with different species or just two quite variable subspecies?  Old World populations may actually represent as many as three additional species. One factor contributing to this confusion is that these shrikes are widely spread geographically, especially in their breeding range, making the collecting of meaningful samples very difficult (Cade and Atkinson 2002).