Thursday, June 30, 2011

Red Crossbill

A pair of Red Crossbills also fed at the Missoula bird feeder.  I was excited as, despite my banding many Red Crossbills,  I have mysteriously never photographed one. These photos are of the male, the female escaped my lens.  The curiously crossed bill is adapted as a conifer cone opener.

Birders have long recognized that Red Crossbills come in different sizes. One winter in Aberdeen I had a single flock of large and small crossbills visiting our feeder.  The size correlates with the size of the cones on which the birds feed.  Crossbills are nomadic and breed when a flock finds plenty the correct sized conifer cones.

Ornithologists next discovered that the different sized crossbills have distinct calls.  Furthermore, even when they breed in the same forest, birds with different calls do not interbreed.  Therefore we may have at least eight different species of red crossbills in North America!  Sibley's website discusses this situation and provides some interesting links.

Wednesday, June 29, 2011

Evening Grosbeak

After the Badlands, the next stop on our western expedition was Missoula, Montana.   We visited friends who keep a bird feeder.  We were greeted by a pair of Evening Grosbeaks, old friends from the Minnesota North Woods.  These grosbeaks breed across Canada and the northernmost United States,  then south through the Rocky Mountians as far as southern Mexico.

Evening Grosbeaks are irruptive migrants, in the United States usually appearing in two-year cycles. Relatively recently Evening Grosbeaks have expanded eastward.  One hypothesis is that this range change is due to the planting of Box Elders in eastern cities.  Box Elder seeds are often abundant all winter, providing the grosbeaks with plenty of food.  Grosbeaks also favor Spruce Budworms, and the birds may have expanded their range after particularly big budworm outbreaks (Gillihan and Byers 2001). I have banded Evening Grosbeaks in northeastern South Dakota and saw them during the winter as a boy in Virginia.  I am told that recently grosbeaks are seldom seen in the southeast.  I am surprised that I have not seen an Evening Grosbeak in Rice County.

My mentor Roxie Laybourne once showed me a gynandromorph Evening Grosbeak.  This bird was half male and half female.  It was yellowish on the right side, gray on the left, with a sharp line of demarcation between the two.  Furthermore, the ovary was on the left side and the testis on the right.  In other words, a testis lay under the female-plumage and an ovary under the right.  This specimen and photographs of other gynandromorphs can be seen by clicking here.  I have also seen a specimen of a gynandromorph  Great-tailed Grackle, large on one half, small on the other.  I have no idea how that bird survived in the wild.

Tuesday, June 28, 2011

Orchard Oriole

Orchard Orioles breed east of the Rocky Mountains, with highest densities in the northern Great Plains and the Southeast.  In Minnesota they are uncommon, with most seen in the southwest (Eckert 2002).  Erika and I found this second-year male on the Carleton College campus on 24 June 2011. (First year males are greenish like the females, but have black throats.) Orchard Orioles nest late in the spring and raise only one brood.  Where they are common, Orchard Orioles breed in loose colonies, with many nests in a single tree. They return to their Central American wintering range as early as mid-July (Scharf and Kren 2010).  This early departure results in few sightings during the fall migration.

Monday, June 27, 2011

Ebony Jewelwing

Upon our return from Olympia, on 24 June 2011, Erika and I strolled by the flooding Cannon River in the Carleton College Arboretum.  We happened upon this exquisite Ebony Jewelwing, a damselfly of eastern North America.  True to the text in, this jewelwing inhabits wooded stream-sides.  The adults perch on low shrubs lit by openings in the forest canopy.  We found this female to be quite wary, but it never fluttered far, landing repeatedly on nearby sunny leaves, until finally disappearing into the dense shrubbery.

Sunday, June 26, 2011

Prairie Dogs and Burrowing Owls

One of the many birds we missed during our western jaunt was the Burrowing Owl.  (The photo below is of an owl taken in South Dakota a few years ago.) Often finding Burrowing Owls is not difficult if you scan Black-tailed Prairie Dog colonies.  We found the rodents in the Badlands National Park but came up empty in the owl department.

Prairie dogs are extremely susceptible to plague. Plague, of course, can be transmitted to people who come in contact with prairie dog fleas.  So rolling around in prairie dog towns is not advised, especially if you do not often bathe.

Black-tailed Prairie Dogs are despised by many ranchers who go to great lengths to eradicate them. Ranchers could control prairie dogs by keeping their range-land in excellent condition, since the rodents prefer poor quality range-land.  In any case, as populations declined, the Fish and Wildlife Service created a political maelstrom by suggesting putting prairie dogs on the Endangered Species Act Candidate Species List.  The agency capitulated in August 2004.

Burrowing Owls nest and roost in empty prairie dog burrows.  Zuni Indians called this owl the “priest of the prairie dogs."  (This quote and much of the owl data are from Haug et al. 1993.) Burrowing Owls are out in both daylight and during the night.  Fortunately for the owls, they are not restricted to prairie dog burrows. Also utilized are burrows of ground squirrels, badgers, marmots, skunks, armadillos, kangaroo rats, and tortoises. They rarely dig their own burrows. Burrowing Owls have an interesting distribution--western North America south through Mexico and Central America, but also Florida, the Bahamas, western Cuba, and Hispaniola.  Isolated populations also occur in South America. Burrowing Owl populations are declining across most of its range. Being hit by cars is the major cause of mortality because the owls often feed on roads at night.

Saturday, June 25, 2011

Lark Sparrow

Another good birding location in South Dakota's Badlands National Park is the Cedar Pass nature trail.  Uncharacteristically, we did not observe many birds during our visit.  An exception was a tame Lark Sparrow, a species I previously tried to photograph with relative lack of success.

Erika commented, "This Lark Sparrow is really posing!"  The sparrow strutted, holding its head high. I learned from Martin and Parrish (2000) that, unlike other songbirds, Lark Sparrows perform "turkey-like strutting with tail upright, flashing white tail spots, and wings dropped to the ground." Females often use nests abandoned by other species.

Lark Sparrows breed across much of the western United States.  Formerly this sparrow also bred to the Atlantic coast, but its breeding range has been receding--now it is found east only across Minnesota and Iowa.  Hypotheses for this retreat include the reforestation of eastern fields and the spread of urbanization. A Lark Sparrow was one of the first rare birds I ever recorded--a bird at our Virginia bird feeder.  Most years I see a few in Minnesota.  They become common in western South Dakota.

Friday, June 24, 2011

Western Birds

Where does western North America begin?  Even though all three of the birds in this post can be found in Minnesota, they are more associated with the west.  As a imprecise rule of thumb, the West begins at the 100th meridian.  In central South Dakota, that line runs just east of the Missouri River. On our recent road-trip we took a short detour through the Badlands National Park in western South Dakota.
Western Meadowlarks greeted us at the park entrance.  In most of South Dakota, unlike in Minnesota, identifying Eastern from Western meadowlarks is not too much of a challenge--Western Meadowlarks are usually the only species present.  Identification was confirmed by the Western Meadlowlark's loud, gurgling, "Have you planted your wheat yet?"  This call is quite unlike the Eastern's lazy "Sweet Sue" whistle.
An excellent location to find birds in the Badlands National Park is at the park headquarters. Western Kingbirds hawked for insects over the parking lot.  Notice the white edge to the outer tail feathers. 
Mountain Bluebirds are more restricted to western North America than are the two previous species.  But even they occasionally stray east to Minnesota.  This individual must have been nesting nearby, as evidenced by the grub it grabbed from the lawn in back of the park headquarters. 

Thursday, June 23, 2011

Black-billed Magpie

Erika and I are just back from a quick road-trip to Olympia, Washington. We had a good time visiting family but were generally disappointed with the relatively low numbers of birds we listed.  Fourteen hour days in the car probably did not help but, for us, definitely beat flying. Obligations back in Northfield kept us from dallying.

In our unscienctific survey, however, we thought we saw more Black-billed Magpies than in previous western trips.  North American magpie populations, found in the northern Great Plains and northern Minnesota, are said to be stable.  In the Dakotas and in Nebraska numbers falling (Trost 1999). Magpies often eat poisons left to kill predators.  Also a pesticide called Warbex is often sprayed on cattle to control fly larvae.  Magpies often pick these larvae off cattle and die by ingesting this organophosphate.  West Nile Virus may also take a toll.

Magpies live in harsh climates in North America.  Magpies use their black and white plumage to regulate their temperatures. In the cold, they face their warmth absorbing black breasts towards the sun.  In the heat, they perch with their reflecting white sides against the rays of the sun.

Tuesday, June 21, 2011

Swamp Sparrow

Swamp Sparrows are common across Minnesota.  They breed in thick cattail swamps, wet meadows, and marshes where they are more often heard than seen.  They nest just above the ground or water--nests sometimes fail due to high water. During migration, however, Swamp Sparrows are often found in drier habitats and even visit bird feeders.  I usually band several during the spring migration.

Saturday, June 18, 2011

Bufflehead Behavior

Last spring I searched for duck pairs.  The perfect Bufflehead photograph has eluded me.  This photo, from the Dennison sewage ponds, is perhaps my best attempt.  This male swam near two hens.  Suddenly one of the females lit out after the male, apparently chasing him away.  Later she joined the other female. You can see the action in the photograph below.

As best I can guess, this behavior may be an example of a "Following Display."  Females often run on the water to catch up with a displaying male. This display is considered to be evidence that the birds are paired (Gauthier 1993).  The only problem with my hypothesis is that the male in my photo seems to be running from the female for dear life!

Update:  Bill Marchel points out that the bird chasing the male below is most likely a second-year male that has not molted into breeding plumage.  Sibley's guide indicates that some young males do not transition to breeding plumage until their second July.  Sex is told by the shape of their face patch--much longer and less oval than that on a female.  The bird above is probably a female, the birds below, males. In fact, the behavior I saw did seem to be more like male to male aggression than the cementing of a pair bond.

Common Merganser

This photograph is another result of my spring project to photograph pairs of waterfowl.  These Common Mergansers posed on Circle Lake in Rice County.  Because they tend to winter as far north as they find open water, Common Mergansers are early migrants in Minnesota. They can be found all winter on Lake Superior.

The drake is easy to identify.  The hen can be tricky to separate from the hen Red-breasted Merganser.  One key to identification is the sharp line between her brown head and gray neck.  Other differences include bill and crest shapes. I previously blogged on these subjects.

As the top predator in aquatic food chains, Common Mergansers are sensitive to the presence of pesticides, mercury, and the effects of acid rainfall.  The salmon and trout industry accuse mergansers of preying on these sport fishes. Mergansers, consequently, have been the targets of eradication programs. North American populations, nevertheless, are stable or increasing (Mallory and Metz 1999).

Friday, June 17, 2011

Sedge Sprite

Erika's garden has Sedge Sprites! How cool is that?  Just as fairytale sprites, they are difficult to photograph.  Sedge Sprites are so small that they give the camera's autofocus fits.  As they hunt for small insects, these damselflies cruise low within vegetation, further confusing focus.

Tiny but beautiful, Sedge Sprites' eyes are azure, their backs emerald, and their abdomens green or bronze.  The tip of the males' abdomens are tipped bright blue. These sprites are common across the central and northern United States and northwest into central Canada.

Thursday, June 16, 2011

Painted Turtle

Painted Turtles are found from the northwest United States, across the northern Central Pains, east to New England and the Southeast. They are commonly kept as pets, and feral populations are established outside their native range in California, Arizona, Florida and even worldwide to Germany, Indonesia, the Philippines, and Spain. In these exotic locations, Painted Turtles have been known to out compete native turtle species.

I encountered this Painted Turtle near Circle Lake, Rice Co., on 12 April 2011.  These turtles hibernate during the winter and warm themselves with radiant heat in the spring.  To be active, the turtle must maintain an internal body temperature between 63 and 73 degrees F.  As adults they have few predators aside from raccoons; adult Painted Turtles have lived up to 55 years in the wild. They are prone to being hit by cars, suffer from habitat loss, and, in some locations, are adversely affected by the pet trade. Nevertheless, Painted Turtles are our most abundant turtle (Wikipedia).

Tuesday, June 14, 2011

Red-winged Blackbird 2

For years, Erika and I taught an environmental education lesson to all the sixth graders in Aberdeen, South Dakota.  We showed the children birds and asked them to make up names.  Male Red-winged Blackbirds presented no problem.  Either the students already knew what a Red-winged Blackbird was, or the species is easily named from its color patters.

The kids had trouble with the bird in the photo above.  Both they and their teachers were often amazed that this streaked bird is a female Red-winged Blackbird.  I was surprised that, despite many Red-wing photographs, I had none of the female.  This spring I remedied this omission at the River Bend Nature Center in Faribault.

Our students yelled "Yellow-headed Blackbird" when they saw the bird below.  They were crestfallen, however, when I replied "Wrong!"  The teachers twittered but the students were delighted when I continued, "Black-assed Yellowbird!"  This blackbird breeds in prairie marshes of the northern Great Plains of the United States and Canada and is found east into Minnesota and Wisconsin.

Sunday, June 12, 2011

Red-winged Blackbird

Among Red-winged Blackbirds, females migrate further south than males. Males, therefore, reappear and begin staking territories in the Minnesota spring before the females arrive.  (Older males migrate shorter distances than first-year males.)  This male was singing on a bush near Circle Lake, Rice Co., Minnesota on 27 April 2011.  What do Red-winged Blackbirds sing?  Some say "Con qer ree."  Others transcribe the song to be "Purple rear!"

Red-winged Blackbirds are one of the most polygamous of birds.  Wealthy males (as measured by quality of their territories) can mate with up to 15 females, who nest in his territory.  The advantage to the male is probably obvious.  Presumably the female who shares a wealthy mate is more successful at fledging her young than if she mated with a "poor" male.  This phenomenon, however, gets more interesting.  DNA studies show that a "wealthy" territory holder has not necessarily fathered all of the young in his territory.  Females, like the males, often copulate with more than one partner, even during a given nesting attempt (Yasukawa and Searcy 1995).  I will leave the explanation to you.

Saturday, June 11, 2011

Bumblebee Moth

The Bumblebee Moth (Hemaris diffinis), also named the Snowberry Clearwing, is a bumblebee mimic.  These diurnal moths are variable in appearance and are often more banded than the individual feeding on azaleas in Erika's garden. They also sip nectar from a wide variety of other flowers, usually in open habitat like fields and gardens. Bumblebee Moths are found across much of North America.

Friday, June 10, 2011

Twelve-spotted Skimmer

On 8 June, I strolled through Erika's garden.  As I idly watched the female Common Whitetails (see June 7th's blog post), I was startled as I immediately recognized this dragonfly is different!  The yellow stripe down the sides of its abdomen is not jagged.  Instead it forms a straight line--the hallmark of the female twelve-spotted Skimmer (Mead, Dragonflies of the North Woods).

I have yet to spy a male Twelve-spotted Skimmer--with his additional white wing bars, he must be a beautiful arthropod.  Despite the presence of many females, I have also not seen a male Common Whitetail in the garden.  I asked my dragonfly authority, Scott King, about this plethora of females and absence of males.  He replied that, until they are ready to mate, female dragonflies often travel far from their natal ponds.  Erika's garden provides perches for these itinerant females and our water feature produces a ton of delicious blackflies.

Thursday, June 9, 2011

Singing Prairie

Gerry H. and I drove about Scott and Dakota counties, despite record-breaking 103-degree temperatures and howling winds on 7 June.  We searched unsuccessfully for Henslow's Sparrows and Hooded Warblers. But just north of Randolph, Minnesota, despite these less than ideal conditions, we found three prairie birds blasting away with their songs.
This year appears to be a banner year for Dickcissels in our region.  You may recall from a previous post that this species tends to be nomadic, with greatly fluctuating annual numbers (June 5, 2010). This bird was one of many on territory on this grassland.  Dispite our photographing and occasional heavy truck traffic, this bird repeatedly returned to his post.  All the while he sang, "Dick-ciss-ciss-ciss."
Fewer Savannah Sparrows also sang in the prairie.  They sing a dreamy, lisping "tsit-tsit-tsit, tsee-tsaaay." Savannah Sparrows are identified by their yellow lores (barely visible in this photo).  They often have central breast spot, where it not for the yellow lores, could be confused with Song Sparrows.
We saw one Grasshopper Sparrow, which obligingly sang his "pi-tup-zeeeeeeeee" as he perched atop another post in the grassland.  One problem is that, in my old age, I no longer hear the "zeeeeeeeeeee."  Instead I hear the "pi-tup" and know that the "zeeeeeeeeee" is being sung only by the bird's open beak.  The sparrow in this photograph is a rather pale individual.  Notice that, like a Savannah Sparrow, its lores are yellow.  The bend of the wing is also yellowish, a field mark not mentioned in many field guides.  Unlike the Savannah Sparrow, this sparrow has unstreaked underparts.

The songs in this blog are used with permission from Thayer Birding Software and the song quotes are from Roger Tory Peterson's Eastern Birds. Details on both publications are in the recommendation box at the right of the blog post and can be seen by clicking on the links in this paragraph.

Wednesday, June 8, 2011

Odd Brown-headed Cowbird

On a recent stroll in the Carleton College Arboretum, Erika and I flushed a male Brown-headed Cowbird.  Knowing that I have more photographs of female cowbirds than of males, I focused my camera on the bird, which had perched atop a nearby bush.  I immediately realized this cowbird was odd--it sported a golden collar.  I am not sure of the cause of this abnormality.  Perhaps it is attributable to xanthochroism, where birds have unexpected yellowish plumage caused by genetic mutation or by diet.  This condition, however, is usually seen in red-plumaged birds.  Another possibility is that this odd color was caused by abnormal feather ware, either due to feather mites or other damage. (I've previously posted about Brown-headed Cowbirds in May 2010.)

Tuesday, June 7, 2011

Common Whitetail

On 4 June I discovered this female Common Whitetail in Erika's garden.  Identification depends on the wavy yellow line down the dragonfly's abdomen and the black wing bands.  The next day I found a male along the shore of the small pond near the entrance to Carleton's lower arboretum.  Adult males, like the one in the photo below, show a striking powdery, white abdomen, which is used in territorial displays.
Common Whitetials are found over much of North America and south into Mexico. They usually feed near water, and prey upon a variety of small flying insects. The nymphs, which are often abundant, are an important link in aquatic food chains. They feed upon aquatic insect larvae, crayfish, tadpoles and minnows but, in turn, are eaten by fish, frogs, and waterbirds.

Monday, June 6, 2011

Maidenhair Fern

On Friday, Erika and I came upon this fine stand of Maidenhair Fern (Adiantum pedatum) along a cliff-side along the Cannon River Bike Trail in Goodhue County.  This fern grows in moist locations under deciduous forests.  The species is found in most of eastern North America.  Native Americans made a tea from the leaves to cure various respiratory conditions; the stems were used in basket weaving (try Googling "maidenhair fern basket").
Apparently the leaves easily shed water, hence the generic name "Adiatum," which derives from the Greek for non-wetting.  The specific name, "pendatum" refers to the shape of a bird's foot. I have wondered about the derivation of the common name.  According to Bill Bryson, many traditional names for plants (and animals) were decidedly vulgar yet unwittingly survive in modern English; "Maidenhair ... does not refer to the hair on the maiden's head." I suppose I should pull one of these ferns up and check its roots, which have fine, dark hairs. Until then, here is a website with a photograph.

Saturday, June 4, 2011

Boreal Bluet

This female damselfly is probably a Boreal Bluet, Enallagma boreale. According to Scott King, my local Odonate expert, they are "impossible to separate from the Northern Bluets except under the microscope."  Females are even harder to identify than males. In Rice County, Northern Bluets are more often found near large lakes.  "So the odds favor the Boreal," concludes Scott. Boreal Bluets are are found in the northern United States and Canada. They are found near ponds and slow streams. Boreal Bluets are usually common and widespread, early-season damselflies.

Thursday, June 2, 2011

Common Grackle

Many birders hold Common Grackles in low esteem. Familiarity may breed some contempt.  Grackles are among the most abundant North American birds. They thrived with the clearing of eastern forests and moved west with the planting of shelter belts. Grackles are omnivorous, and their diet includes smaller birds; they are known to rob nests and eat hatchlings and eggs. Grackles can take over a summer bird feeder and the species causes extensive crop damage.

Common Grackle numbers can be phenomenal. Populations have been estimated at over a million birds in several eastern states.  Recently, however, grackle numbers have been declining--perhaps as a result of control measures. Decreases of as much as a third have been reported from Breeding Bird Surveys (Peer and Bollinger 1997).

When I discovered that this common species was not illustrated in my blog, Erika and I initiated a grackle search. We quickly discovered our bird on a piece of rusted farm machinery near Northfield. Even as I took these photographs, I was amazed by this displaying male's beauty. Previously, I did not appreciate the iridescence of a sunlit grackle. If you look carefully at the first photo, you may notice that its nictitating membrane is half closed. I was surprised to see that it is blue.
Common Grackles are not normally found west of the Rocky Mountains. An exception was a grackle that I banded in Aberdeen, South Dakota on 8 August 1994. On 10 August 2000, this bird was recovered in Vancouver, Washington. At the time, this record was only the seventh for Washington state.  Some confusion exists, however, since the finder of the bird does not remember reporting it.

In my book, Birds of South Dakota, I studied bird banding recoveries. I found that most South Dakota grackles winter in Arkansas (at least as evidenced by recovery records). Red-winged Blackbirds tend to winter further west, in Texas. Finally, most Yellow-headed Blackbirds winter in western Mexico.

Wednesday, June 1, 2011

Clay-colored Sparrow

Clay-colored Sparrows are abundant in disturbed, bushy prairies in the north-central United States and in the Canadian prairie provinces.  I photographed the top bird on 24 May 2011 in brushy pastureland near Northfield.  The dark cheek patches and gray nape are diagnostic field marks.

Clay-colored Sparrows feed outside their breeding territories, which include little space beyond their nests.  Clay-colored Sparrows are assumed to be monogamous.  During migration this sparrow travels with other sparrow species; most individuals winter in central Mexico. 

I took the lower photograph at River Bend Nature Center near Faribault on 30 April 2011.  Notice that the Clay-colored Sparrow in the foreground lacks the gray face and rusty crown of the Field Sparrow feeding alongside.  The Field Sparrow's bill is also much brighter pink than the pale bill of the Clay-colored.