Blue-gray Gnatcatcher

In May, I found this female Blue-gray Gnatcatcher in Rice County's Cannon River Wilderness Area. Luckily gnatcatchers are fairly early migrants in Minnesota, because the birds become relatively hard to see after the trees leaf out in the spring. Often the only indication of their presence are their high-pitched calls. Our gnatcatcher is found across much of North America, south through Central America. Other species are found in the American Southwest and in Latin America. Ours is the only truly migratory species. In the past 25 years, gnatcatchers have expanded northward (Kershner and Ellison 2012),

Yellow-headed Blackbird

The last year or two, I have found Yellow-headed Blackbirds more frequently in eastern Minnesota. This bird was perched on the side of a road in Dakota County in May. These blackbirds prefer deep-water cattail marshes and are found in much of western North America.

Yellow-headed Blackbirds are polygynous, often with up to 16 females in a harem. Productive lakes have more females than poorer ones, and more females per male. Unfortunately, what with my new-found interest in odonates, productive marshes are usually defined by high rates of dragonfly emergence. In the winter, these blackbirds eat grain.

Males defend their territories against other males and usually do not breed until after their second year. Females defend small areas around their grouped nests. Females, however, will copulate with “any observed male,” usually those males with adjoining territories when the female's mate is absent (Twedt and Crawford 1995).

Purple Martin

On 4 June 2014, John Holden came upon a pair Purple Martins on a dirt road in the village of Warsaw, Minnesota. This behavior is reported for this largest of North American swallows. Tarof and Brown (2013) write that martins use fine bits of gravel to help digest insect exoskeletons. Martins do not feed in flocks, but often in pairs—the result of mating-guarding by the males.

Martins consume dragon and damselflies as well other arthropods. such as beetles, bugs, flies, grasshoppers, butterflies and moths (and their caterpillars), wasps and bees, and even termites. I have previously written about martin diets. Tarof and Brown report that no credible data exist that Purple Martins eat mosquitos, despite the popular belief to the contrary. For one thing, martins tend to feed high in the air (sometimes up to 450 feet), whereas mosquitos stay near the ground.

I also wrote about Purple Martin range. Since that post, some fascinating research with geolocators has appeared, as reported in the Forest Lake Times. Here you can find maps of routes taken by two Minnesota Purple Martins to the Brazilian Amazon Basin. One bird flew over the Gulf of Mexico and down through Central and South America and returned by the same route. The other took the same path north in the spring, but, during the fall migration, visited the length of Cuba before continuing to Brazil.

Four-spotted Skimmer

Another dragonfly I encountered during my expeditions to the Carleton College arboretum is this Four-spotted Skimmer. Males and females are often not distinguishable in the field (at least by humans). See my previous post on this species. Paulson writes that the males of this species are highly territorial, but tolerate “satellite” individuals.  These individuals are non-mating, subordinate males.

Four -spotted Skimmers are found across much of North America, all the way to Alaska. They are also found across the Old World, from Great Britain to Japan. Four-spotted Chasers, as they are known in England, are migratory in Europe, but such behavior is unrecorded in the New World.

Dot-tailed Whiteface

For the past two days I have been searching the Carleton College arboretum for a snaketail, a kind of dragonfly, but without success. I have seen about a half-dozen other species of odes, including this lovely male Dot-tailed Whiteface. Summer seems to have finally arrived. The basis for this name should be patently obvious from this photo.

In most of the northern United States and in southern Canada, this species is the most frequently encountered white-face. I have blogged about it before. According to Paulson, Dot-tailed Whitefaces keep fixed territories, but do not defend them aggressively. Other males can fly through a territory, but are not chased unless they come relatively close to the territory owner.

Cedar Waxwing

I’ve been on the lookout for a Cedar Waxwing with red waxy tips to its secondary feathers, and this May I caught one. The bird in the photo looks a bit strange because I have photoshopped my hand away. Both sexes of waxwings have these red tips, which may serve as a status signal in mate selection. Older birds have more red tips than younger ones. Birds tend to pick mates with a similar number of waxy wing tips. The red tips were once thought to protect the feathers from wear as waxwings frolic in cedars, but this hypothesis is no longer supported by most ornithologists.

After taking a photo of the spread wing, I held the bird further away to include an image of the waxwing’s yellow tail band. To my surprise, when I developed the picture, I noticed some of the tail feathers also have red tips. I can find no mention of this plumage trait in Witmer et al. 1997, although a photo in their account shows a tail with much less distinct red tail feather tips. 

Waxwings with orange-banded tails were first observed in North America in the early 1960s and are becoming increasingly common. (See my first-ever post in this blog.) Apparently this orange color is due to the waxwings’ eating Morrow’s Honeysuckle, an introduced plant that has now become fairly common. The honeysuckle contains rhodoxantin pigments, which, if eaten at critical times of feather growth, change the color of the tail band. 

P.S. Roger Everhart directed me to this link: http://www.birdvancouver.com/blog_spring_2014.html.

Curve-billed (Plateau) Thrasher

Next up at the Edinburg, Texas, bird feeder on 21 February 2014, was a Curve-billed Thrasher. This species probes in the ground litter for insects and seeds. It also consumes berries and cactus fruit. Curve-billed Thrashers are tolerant of a range of habitats and seems to coexist with people. Just how this thrasher will survive the extreme development of the Texas brush country, however, remains to be seen (Tweit 1996).

Curved-billed Thrashers in the Arizona Sonoran Desert and northwestern Mexico may be a different species from those in the Chihuahuan Desert, Texas, and central Mexico. The two populations do not overlap and their mitochondrial DNA differs. Among other field marks, eastern birds have light breasts, which make their spotting more distinct. Western birds have grayer breasts, with resultant less distinct spots. Western birds also have less distinct wing-bars. Compare this Texas bird with one I took in 2012 in southern Arizona. For the time being, the two populations are considered to be subspecies. But the question of splitting Curve-billed Thrasher into an eastern Plateau Thrasher and a western Palmer's Thrasher is currently on the agenda of the American Ornithologists' Union's checklist committee.

Wilson’s Phalarope/Lesser Yellowlegs

Last winter, Scott King and I made a deal. If I showed him a Lesser Yellowlegs, he would find a dragonfly I need for my list. I feel a little guilty about this deal, since I knew I’d be fairly safe in finding the yellowlegs. These three Lesser Yellowlegs strolled behind a female Wilson’s Phalarope this May at the Great Western Industrial Park near Randolph, Minnesota.

The phalarope is less common than the yellowlegs. I have previously posted on the species. Most birders know of their reversal of sex roles. Female phalaropes are larger and more brightly plumaged than their males. The females often mate with more than one male. The male provides all parental care of the young.

Lesser Yellowlegs’ breeding cycle is less well known to birders, but is also interesting. Males court females and both parents incubate their eggs. Both sexes vigorously defend their territories and care for their precocial young. Females, however, tend to migrate from their breeding areas before their young can fly, leaving the males to become the sole defenders of the chicks (Tibbitts and Moskoff 2014).

Virginia Rail

On 28 May 2014, John Holden and I checked out Swan Lake in nearby Nicollet County, Minnesota.  We listened for the Virginia Rail “grunt” call. Check it out if you have the Sibley Bird app on either your Android or iPhone. Out of the cattails, strolled two Virginia’s Rails. Note the long toes of the bird in the first photo.

These small rails are lovely creatures. One of our rails circled, fed, and occasionally grunted at us. The rails give back-and-forth, grunting duets during courtship. These are specialized calls used in pair bonding. 

Male Virginia Rails are larger than the females, but can not otherwise be told apart in the field. Virginia Rails are dietary generalists, eating much of what comes their way—invertebrates, small fish, and seeds.

In the last photo, the rail seemed to stick its tongue out at us. I am not sure what the object is toward the end of the tongue—an ant?  Or just some dirt?

Review: Britain’s Dragonflies

My first photograph of a dragonfly in Minnesota for 2014—a Twelve-spotted Skimmer found in Rice County on 30 May. One of the delights of dragonfly watching in Minnesota is the diversity of odes (odes is short for Odonata, the order containing the dragonflies and damselflies). Rice County, not a huge area, has a list of 74 species. The United States and Canada supports some 450 species.

Compare those numbers with Britain and Ireland’s total of 56 dragonfly and damselfly species. Dave Smallshire and Andy Swash have recently published a new edition of their guide, Britain’s Dragonflies (sample pages can be seen by clicking the link). This book will delight any dragonfly enthusiast. This 224-page field guide, covering so few species, has plenty of room to excel.

The species accounts contain 450 large, color photographs. Five hundred and fifty diagrams of important field marks are also included. Males, females, immatures and all color phases for every species are illustrated. A small map indicates where to look for species. Short paragraphs include descriptions, behavior, habitat, and conservation concerns. Boxes at the end explain where and how to look for each species and how to separate each dragonfly from similar species.

The beginning of the book describes dragonfly anatomy, ecology and life cycles. Also covered are interesting subjects such as where to look for dragonflies and what to look for when beginning to identify them. What really sets this book apart, however, are the last 20 pages that cover how to identify dragonfly nymphs, the aquatic immature stages. Almost no field guide of North American dragonflies includes comparable material.

With a photograph of a fire-breathing dragonfly in the preface, this book even includes humor. The wonders of photoshop never end… One item missing from the book, however, is a paid-in-full ticket to London. Very few of Britain’s dragonflies or damselflies are found in North America. I wish we had a comparable book for Minnesota.