Saturday, April 30, 2016

White-throated Sparrow

White-throated Sparrows are abundant spring and fall transients through southern Minnesota. The following paragraphs are from my free, on-line ornithology course:

White-throated Sparrows winter in the southeastern US, breeding across Canada and parts of the northern United States. During early spring, birds store large amounts of fat as an energy source during migration. Reproductive development occurs during spring. Following June breeding, gonads regress and remain small until next spring. These events (fattening and gonad size increase) and migratory restlessness and orientation towards north or south are all affected by prolactin from the pituitary and corticosteroids from the Adrenal cortex.

A. H. Meier injected corticosteroids into White-throated Sparrows at time zero. Prolactin given at 12 hours results in: rise of fat stores, rise in gonad size, rise in migratory restlessness and a rise in locomotor activity towards north (= spring migrant). Prolactin given at 4 hours results in arise in fat stores, rise in migratory restlessness, no gonad increase, and an orientation to south (= fall migrant). Prolactin at 8 hours decreases fat stores, decreases locomotor activity, and decreases gonad weight (= winter bird).

This does not explain how the bird knows which way is north or South.

Friday, April 29, 2016

Yellow-headed Blackbird

John Holden and I photographed this Yellow-headed Blackbird at Dakota County’s 180th Street Marsh on 27 April 2016. Minnesota and Wisconsin are about as far east as this western species breeds. I have written about this species before, including in June 2014.

Males winter further north than do females. The males migrate one to two weeks before the females. The center of their wintering range is throughout the Mexican Central Plateau, but they are also abundant in the winter in southern Texas and New Mexico. Scattered winter records exist elsewhere, even in Minnesota. The species has been seen in Europe, though these vagrants may be escapes from captivity (Fraga 2016).

Thursday, April 28, 2016

Red-winged Blackbird

On 20 April 2016, one of the most curious birds that John Holden and I saw at Dakota County’s 180th Street Marsh was one of the most common. Red-winged Blackbird are abundant. Males sang atop many of the cattails. Among them was a female bird that was apparently defending territory.

Ornithologists are not sure if female Red-wings hold territories. Males are famously polygamous and females are aggressive towards each other. Some researchers maintain that females hold sub-territories within the male territory. But these sub-territories seem to overlap, and singing females do not usually drive away intruders. The status of a female within a male’s territory depends on several factors, including how long she has been mated and her distance from her nest (Yasukawa and Searcy 1995).

Tuesday, April 26, 2016

Tufted Titmouse

We found this titmouse at the Ray Roberts Lake State Park near Denton, Texas, on 17 March 2016. Tufted Titmice are abundant across most of eastern North America, but less so in the north. Their range, however, is expanding northward. This change may be due to global warming and/or increased use of bird feeders by birders.

The titmouse’s song, “peter-peter-peter-peter” is a dominant sound in most forested areas of the southeast. Titmice are a “nuclear species” in mixed flocks of forest birds. The other species follow the titmice, which often know where food supplies lie or where feeders exist.  Titmice also aggressively mob predators, thus alerting the other birds of danger (Ritchison et al. 2015).

Monday, April 25, 2016

Bleeding Heart

About 20 species of Dicentra, Bleeding Heart, a poppy, are found around the world. Cultivated Bleeding Heart originally grew in Asia. Now the plant is introduced around the world. A popular garden plant, Bleeding Hearts require minimal care. To keep them from taking over her garden, Erika must cut and weed these perennials. Ants disperse Bleeding Hearts. Ants collect lipids found on Bleeding Heart seeds. The arthropods take the seeds to their burrows, where ants eat the lipids, but do not damage the seeds. The plants also attract hummingbirds, which are their main pollinators.

Bleeding Hearts should be handled with care. They are poisonous, causing rashes in some people and sometimes killing cattle. Deer avoid Dicentra. No species of Dicentra should be ingested. Indigenous Bleeding Hearts were used by settlers and Native Peoples for the treatment of sprains, bruises, and insect bites. The plant is eaten, however, by some butterfly larvae, snails, and aphids (Softscholls.com; Buzzle).

Sunday, April 24, 2016

Large-flowered Bellwort

Large-flowered Bellwort are found across much of eastern North America, including almost all of Minnesota. Formerly classified as lilies, they are now placed in the closely related family Colchicaceae.

They are common in woodland areas, and are marching up the edge of Erika’s garden. Because we do not remember planting them, these bellworts may be wild volunteers. Other gardeners report that this species can remain dormant for many years, often reappearing after European Buckthorn is eradicated. According to a reader comment in Dave’s Garden website, “Roots, shoots and leaves were used for food by early settlers. In early medicine, it was used as a general stomach remedy, [and] a poultice for wounds and skin inflammations. A concoction from the roots was used for canker sores.”

Saturday, April 23, 2016

Blue-winged Teal

Also from Wednesday’s jaunt to Dakota County’s 180th Street Marsh was a close encounter with a Blue-winged Teal. Whenever I see drake Blue-wings, I am reminded of my seventh-grade teacher, John Trott, who introduced me to birds. He also sparked my interest in reading. He asked my parents if he could give me “The Big Sky,” a rather raunchy novel (at least for a 1960s grade-schooler) about fur trappers in the Dakotas. I never imagined a book could be so cool. In the book, our doomed hero falls in love with a Blackfoot woman with eyes the shape of the moons on a teal’s face.

For more information about Blue-winged Teal, see my post of 5 May 2012.

Friday, April 22, 2016

Vesper Sparrow

Two Wednesday’s ago, John Holden and I found a flock of about a half-dozen Vesper Sparrows. The birds fed along the roadside near Circle Lake here in Rice County. Vesper Sparrows are abundant field birds here in Northfield, and I have posted on the species in this blog. Field marks include the dark cheeks, which contrast with the white eye ring. Especially in flight, the white outer tail feathers are apparent. Not so evident in this photo is the Vesper Sparrow’s chestnut shoulder. Early ornithologists referred to the bird as the Bay-winged Sparrow.

Thursday, April 21, 2016

Pied-billed Grebe

On Wednesday, John Holden and I were lured to the 180th Street Marsh in nearby Dakota County. We were disappointed in the lack of diversity we discovered. But we enjoyed the few birds we did see, like this adult Pied-billed Grebe.

Pied-billed Grebes are opportunistic feeders. They prefer crayfish, but also consume other invertebrates, frogs, and fish. Most of this prey is taken by diving. Dives last about 12 seconds, as the grebe zig-zags after its submerged quarry.  Grebes also occasionally forage off the surface of aquatic vegetation (Muller and Storer 1999).

For more information on this species, see my 8 October 2010 post in this blog.

Wednesday, April 20, 2016

Lesser Scaup

One key to separating Lesser from Greater Scaup is their head shape. Greater Scaup have relatively round head profiles, while Lessers heads have taller hind crowns. Sibley writes, “differences in head shape are easily seen on sleeping birds…Scaup  are often more easily identified when sleeping than when awake.” No doubt that this Texas duck from last March is a Lesser Scaup.

Tuesday, April 19, 2016

Black Vulture

These Black Vultures served as our Texas welcoming committee. We visited Ray Roberts State Park on 17 March. I am surprised that the birds perched with their toes hanging straight out past the edge of the light-post. A more centered perch might give them better balance. Perhaps when they flush, they push off with their toes, and thereby attain airspeed. Last year I posted a note on Black Vultures from this same location.

Sunday, April 17, 2016

Purple Finch

I was delighted when, on 13 April 2016, this Purple Finch appeared at our feeder. This female-appearing bird could be a first-year male. Red males, like the bird in the second photo, take two years to obtain their wine-colored feathers.
I previously blogged about how to tell Purple from House finches. Over the next three days, I banded 10 Purple Finches. The most interesting of these birds was the following individual.
After eating seeds at the feeder, this bird flew up to a maple with sap running down its trunk (see last photo). The bird spent almost a minute drinking from the tree. Curiously, Wootton (1996), in the definitive Birds of North America, does not mention Purple Finches' drinking sap. A cursory internet search came up with a citation by Lange of finches drinking Box Elder sap. In 1900, Lange wondered, in the unscientific magazine Recreationif Purple Finches (and other sparrows) drink sap for the sugar or the water. He suspected water. I think a sugar solution would supply energy for many migrants.

Saturday, April 16, 2016

Stalking the Wild Ephemerals

Two days ago, on 14 April 2016, Bloodroot popped out from under the leaves in our front yard. This Bloodroot patch was our first spring ephemeral to appear last year. One of the highlights of each year is our hunt for these wildflowers. Ephemerals, unable to tolerate shade, are the first flowers to bloom in the spring. They last only until the forest leafs out.

The next day, Erika and I hunted ephemerals at the Cannon River Wilderness Area.  This county park, hardly a wilderness, is near Northfield.  We listed the typical first-blooming wildflowers. Here are the flowers we found, beginning with another Bloodroot. I have linked the species’ names to previous blog posts. There you can find more information on each flower.

Friday, April 15, 2016

Bewick’s Wren

When we arrived in Dallas, on 19 March 2016, a Bewick’s Wren greeted us. Curiously, during last year’s visit, I saw this species in the same bush. At least this year I documented that this species does, indeed, have a tail (see last year’s photo). Actually the tail is a good field mark, as this wren tends to wag its tail sidewise, unlike the somewhat similar Carolina Wren.

Bewick’s Wrens are a poorly studied bird, most common in southeastern Arizona, coastal southern California, and the Edwards Plateau of central Texas (Kennedy and White 2013).

Thursday, April 14, 2016

Cedar Waxwing

From Northfield, Dallas is a straight shot down I-35. This year I decided to avoid Oklahoma City by driving on county roads east of the city. Unfortunately this decision added two hours to our journey. Our route did bring us to Sulfur, Oklahoma, at the edge of the Chickasaw National Recreation Area. Sulfurous spring water ran through several small creeks.

Here we found a huge flock of Cedar Waxwings drinking water. Waxwings love water. These are are one of our most frugivorous birds. The problem in the winter is that the dried fruit they consume tends to cause dehydration. The birds counteract this osmotic stress by drinking water (or snow) (Wikipedia). In the summer, water is not as critical. Then fruits are juicier and the waxwings also supplement their diet with small insects and insect larvae (Witmer et al. 2014).

If you look closely at the flock drinking in the lower photo, you may notice, on the left, a waxwing with a bright red tail tip.  This color, according to Cornell University, is the result of the bird’s eating introduced ornamental honeysuckle berries with red pigments.
 

Wednesday, April 13, 2016

Flicker Flock

Migratory behavior of Northern Flickers is poorly known (Weibe and Moore 2008).  This photo is of a flock of 9 of 14 Yellow-shafted Flickers in a neighbor’s tree last Sunday. Flickers migrate in loose flocks, which range from a few birds to over 100. Geographical funnels, like peninsulas or passes, may increase flock size, but that is not the case here. Weather affects migration rates and times, and, in this case, the day was one of south winds, abruptly swinging north in the mid-afternoon.

Tuesday, April 12, 2016

Golden-crowned Kinglet

Since 2007, I banded 64 Golden-crowned Kinglets in Minnesota. None showed aggression like this male last Sunday. When alarmed by predators or male intruders, Golden-crowned Kinglets erect their crown feathers. This action also indicates agonistic behavior, when a male invades neighboring territories. Combatants expose their crown patches and bow their heads towards opponents (Swanson et al. 2012). Unlike birds in the previous examples, my bird remained silent during our interaction.

Sunday, April 10, 2016

Odd Mallard

We were greeted in Andover, Kansas, on 16 March 2016, by this odd, female Mallard. Mallards escaped from captivity often show strange plumages. Mallards will also hybridize with just about any other duck. George Lowery, Jr., delighted telling his students that, if nothing else was available, drake Mallards will mate with fence posts. This Mallard’s white supercilliary is reminiscent of a Garganey, a European species occasionally seen in North America. I wonder if some ancient Garganey genes have resurfaced in this domestic duck.

Saturday, April 9, 2016

American Sweetgum

On 16 March 2016, Erika and I began a long road-trip through the eastern United States. Wildlife watching proved to be poor on this trip—too many rainy days. Our first goal was to visit grandchildren in Dallas, Texas. 

At a roadside rest area along I-35 in Missouri, we found American Sweetgum,  Liquidambar styraciflua. This tree is a common tree of the southeastern states, used for both lumber and urban cultivation. Many homeowners rue sweetgum trees, as the plants drop their copious, spiny fruit across their lawns. Sweetgum sap has been used as an herbal tea and may fight flu (Dean). This author writes that the sap is not very sweet, but it is not as bitter or sour as Black Gum, Nyssa sylvatica.

Thursday, April 7, 2016

Mallard

Erika spied this gorgeous male Mallard during our hike along the Bass Ponds on 11 March 2016. Ornithologists believe that North American Mallard males and females were initially similarly colored. Mallards with bright males appear to have invaded North America from Asia (Drilling et al. 2002). These males interbred with native populations. Kevin Omland demonstrated that male mallards with bright bills are more successful in mating than birds with duller bills. Males with brighter plumage also had the best pairing success. Males that molt earliest are most likely to find mates.

Monday, April 4, 2016

Acadian Flycatcher

On 27 May 2013, I banded this Acadian Flycatcher. This species is one of the very difficult to identify birds in the genus Empidonax. They are best told about by song. Unfortunately, birds almost never sing while I band them. I based my identification of this flycatcher by the greenish wash to its upperparts.

Acadian Flycatchers breed in the nearby Cannon River Wilderness Area, but I have banded very few. In the Wilderness Area, they are found near creeks. They forage for insects in the lower forest levels. You can find these flycatchers by listening for their “tee-chup” and “peet-sah” songs.

Acadian flycatcher populations appear to be stable across their eastern North American range. The species, however, is vulnerable to forest fragmentation and to cowbird parasitism (Whitehead and Taylor 2002)

Saturday, April 2, 2016

Common Redpoll 2

This year has not been a banner winter for Common Redpolls in Northfield. I banded Common Redpolls on 18 February 2016 and again on 11 March. The March flock contained a few bright red birds. Male redpolls usually take two years to become this color. In their first year, they are much duller, and are not separable from females, which can sport some red.