Monday, February 8, 2016

Dark-eyed Junco

On Friday Erika and I made a brief visit to the University of Minnesota Landscape Arboretum. I was happy to see a small flock of Dark-eyed Juncos. Although a few winter here in Minnesota, most travel further south from their transcontinental breeding range across Alaska, Canada, and some northern and mountain states.

Elsewhere in this blog I wrote about the “turbulent taxonomic history” that has been a “nightmare” for ornithologists. At one time, five species of junco were recognized. These days, there are only two species with at least 15 races (Nolan et al. 2002).

This junco’s brown back that contrasts with the gray head gave me pause. What is this junco?  A western Oregon Dark-eyed Junco?  Or an intermediate “cistomontanus,” a race that has been variously assigned to western Oregon and eastern Slate-colored Juncos?

This bird is probably a first-winter Slate-colored Junco. Its flanks are gray. Females can be quite variable, and may sport brownish backs and/or buffy flanks. The authors cited above write, "many records in East probably pertain to brownish variants of J. h. hyemalis (which are also often confused with oreganus group in the East)."

Saturday, February 6, 2016

Marsh Wren

During John Holden and my visit to nearby Sprague Lake on 20 May 2015, we kicked up this Marsh Wren. Their rich but limited marsh habitat affects these wrens in a number of interesting ways.

You can see that they are adept at making their way through the marsh. They would be hard to find, except that they are almost continually singing. Males learn up to 200 song types, with which they have verbal duels with neighboring competitors. Females may also be attracted to males with rich repetoirs.

Females are attracted to males with rich territories. In some marshes, half the males mate simultaneously with two or more females. Males are so “zealous” that them build multiple nests, some times six dummy nests for every nest used by a female.

This extraordinary competition also leads Marsh Wrens to destroy competitors’ and other species’ eggs. Box sexes of Marsh Wrens destroy eggs that they find. Information and the quote in this post comes from  Kroodsma and Verner 2014.

Wednesday, February 3, 2016

Dancing Dragonflies and Damselflies

I am pleased with the recently published third edition of my book, Dancing Dragonflies and Damselflies. The book is 208 pages, with color photos of about 90 species of odonates, most from Minnesota, but others from our various travels. Since the book is published on an per-order basis, the traditional formats are ridiculously expensive ($80.00 for a paper-bound copy/$89.00 for hardbound).

But, gentle reader, do not despair. I have also produced an eBook for the iPad and a .pdf format for other eBook Readers—The price? A mere $9.99, delivered direct to your device! To order, just click the link, the photo on this post or on the icon in the left column on this blog.

Tuesday, February 2, 2016

Virginia Rail

On 20 May 2015, John Holden and I discovered a Virginia Rail at nearby Sprague Lake. These rails are common, but often hard to see, in local marshes. This individual was fearlessly guarding its territory from us. A rail is able to navigate through the reeds because of its laterally compressed body and flexible vertebrae. Perhaps because of these adaptations, Virginia Rails survive flightlessness during the late summer, when they simultaneously molt their wing and tail feathers (Conway 1995).

Sunday, January 31, 2016

Red-bellied Woodpecker

At the home feeders, we have a a pair of Red-bellied Woodpeckers. As indicated by his red forehead, this individual is a male (click here to see a female). These birds are a bit different from other woodpeckers in that they seldom drill wood for food. This woodpecker prefers fruit, seeds, or arthropods.

Recently Red-bellied Woodpeckers have expanded north and west. Most are not migratory, although some northern populations retreat southward during cold winters (Shackelford et al. 2000). None of my banded Red-bellieds have been captured elsewhere.  I have, however, retrapped a couple of my birds ten years after my banding them.

Friday, January 29, 2016

Red-tailed Hawk

On Wednesday, I was working in our sunroom. I looked up from my computer and noticed a Red-tailed Hawk perched high in a tree near our house.  These hawks are fairly omnivorous carnivores, consuming small to medium-sized mammals (rodents like voles, deer mice, and ground squirrels), rabbits, a wide menu of birds, and a few snakes. Tree squirrels, Red Squirrels, chipmunks, amphibians and insects are infrequently taken by these hawks.

Our Red-tailed Hawk tore apart and ate a Red Squirrel. (We did not see the capture, so we do not know if the squirrel was scavenged.) Prey is often taken to feeding perches, but small mammals are usually swallowed whole. Birds are torn apart and plucked before being eaten. Larger prey is dismembered on the ground and the pieces taken to a perch for dining (Preston and Beane 2009).
While our hawk ate, a second Red-tail swooped down through the forest and landed nearby. I do not know if these birds were a pair, or if they were cooperative hunters. The first hawk paid no attention as the second watched it eat.  Red-tailed Hawks are known to steal food caught by other hawks. (They are also known to eat each other.) After about five minutes, the first hawk flew away, carrying the remains of the squirrel. The second hawk followed deeper into the woods.

Wednesday, January 27, 2016

White-breasted Nuthatch

White-breasted Nuthatches are found in southern Canada, most of the United States, and the mountains of Mexico. Most are non-migratory. They survive our harsh winters by caching food throughout their territories. Although I have no banding evidence for my Minnesota nuthatches’ migrating, in some falls, however, some northern and western birds do move south. Grubb and Pravosudov (2008) caution that it is no known if these wandering birds return to their natal regions or if they breed elsewhere.

Monday, January 25, 2016

Glaucous Gull

Glaucous Gulls enjoy a world-wide arctic range. In the New World, they winter into the northern United States. Erika and I saw several among the gulls at Canal Park in Duluth during our New Year’s search for the Ivory Gull. Like many of its brethren,  Glaucous Gulls ominivores, consuming fish, birds, human refuse, and even berries (Weiser and Gilchrist 2012). The smaller bird to the Glaucous’s left is a Herring Gull.

Saturday, January 23, 2016

Pine Grosbeak

Pine Grosbeaks are another visitor from the far North. They breed around the world, usually further south than the redpolls in the last post. On the other hand, they usually do not irrupt as far south when they are found in the northern United States. Last December I photographed this species in Rice County, which is well south of their normal range. Sedentary Pine Grosbeaks also breed through much of the Rocky Mountains.

This female Pine Grosbeak fed at the feeders at the new Sax-Zim Welcome Center on 3 January 2016. The bog lies about 35 miles northeast of Duluth, Minnesota.

Thursday, January 21, 2016

Common Redpoll

Common Redpolls breed across the far northern latitudes of both hemispheres, where they are often the most common songbirds. They irrupt into the northern United States after spruce and birch seed-crops fail, often in alternating years (Knox and Lowther 2000). In my South Dakota banding studies, I found irruption years hard to predict.

This redpoll fed along with a small flock at the new Sax-Zim Welcome Center on 3 January 2016. Males take two years to become bright rosy. First year males are usually not distinguishable from the females.