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.

Blackburnian Warbler

One of the highlights of spring migration is finding a male Blackburnian Warbler. The bird almost glows among the green foliage. On the breeding grounds, this warbler is usually found high in trees, where it forages for caterpillars. During migration they also are often found in the treetops, although this individual was netted near our water feature.

Blackburnian Warblers, like the Canada Warbler I wrote about in the last post, are threatened by tropical deforestation in their winter range. The species is less frequently seen in their breeding grounds if forests are fragmented or diseased. Nevertheless, Breeding Bird Survey data indicate their numbers are stable (Morse 2004).

Canada Warbler

Canada Warblers are late spring migrants and pass through our area early in the fall. They are faithful mates, with some individuals remaining paired for up to six years (Reitsma et al. 2010). Populations of Canada Warblers are declining about 2% a year—breeding birds suffer from loss of forest wetlands and  the secondary habitat they prefer. Canada Warblers winter along the east slope of the Andes, which are being deforested. I banded this male in late May 2014 in Northfield, Minnesota.

Least Flycatcher

In late May, I photographed this Least Flycatcher in a field near the Cannon River Wilderness Area in Rice County, Minnesota. Although facing away from me, the bird turned its head 180 degrees, making the head appear to be attached backwards on its body.

There are a couple of odd things about Least Flycatchers. The birds, when breeding, tend to cluster their small territories. The flycatchers vigorously defend these territories against other species, such as redstarts and cowbirds. As a result, cowbirds only infrequently parasitize Least Flycatchers. Another strange thing is that Least Flycatcher adults wait to molt until after they arrive in their wintering grounds. Birds of the year molt either before they leave the breeding areas or during migration. Ornithologists do not understand this difference, but speculate that the adults need to arrive early in the wintering areas to quickly establish winter territories (Tarof and Briskie 2008).

Six-spotted Fishing Spider

On 25 May 2014, I was not the only predator searching for dragonflies along a small pond in Carleton College’s arboretum. This Six-spotted Fishing Spider was looking for aquatic nymphs, whereas I was more interested in flying adults. This spider is found across much of the United States and Canada to South America. This species is our most aquatic spider. It hunts along ponds and rivers and even walks on the water surface—it takes water striders or other insects that have fallen onto the water.  It also dives for its prey, which includes small fish, frogs, and aquatic insects, and can stay under water for up to an hour (Wikipedia).

Tennessee Warbler

Here are five Tennessee Warblers feeding on one of John Holden’s jelly feeders. This spring, Erika and I have occasionally seen these warblers at our hummingbird feeder.

In a previous post, I explained why Tennessee Warblers might be better named Coffee Warblers. In any event, numbers of these warblers tend to fluctuate greatly from year to year. These fluctuations are probably due to the species' being a Spruce Budworm specialist. When budworms are abundant, Tennessee Warblers can be the most common bird in eastern Canadian boreal forests. Thirty-year censuses, however, indicate that Tennessee Warblers enjoy stabile populations over the long term (Rimmer and Mcfarland 2012).

Baltimore Oriole

Many of our friends have feeders for Baltimore Orioles, where the birds consume massive amounts of grape jelly. We seldom attract orioles at our feeding station. On Thursday two orioles appeared at our hummingbird feeder. I can not recall seeing orioles at hummingbird feeders, and we quickly put up a jelly feeder. The orioles fed at both feeders most of the afternoon. We have not seen either bird since.

I have previously blogged about some of the Baltimore Oriole’s strange taxonomy. Males do not acquire their brilliant plumage until the fall of their second year. Until then, they resemble females. These drab, spring, second-year males do occasionally attract mates and successfully raise young (Rising and Flood 1998). Baltimore Orioles are usually seasonally monogamous.

Our orioles are in the blackbird family. They are named for their superficial resemblance to Old World Orioles, a completely different bird family. Mark Catesby named the Baltimore Oriole in 1731, calling it the “Baltimore Bird,” since orange and black were the family colors of the Baltimores of Maryland Colony.

Magnolia Warbler

As I have previously written, the Magnolia Warbler owes its name to Alexander Wilson’s collecting the first specimen from a Mississippi magnolia tree. Considering the species’ northern breeding habitat, better names might have been Spruce Warbler or Hemlock Warbler. Magnolia is actually the bird’s scientific name and Wilson’s English name was Black-and-yellow Warbler (Dunn and Hall 2010). By any name, Magnolias are among our more strikingly beautiful warblers.

Chestnut-sided Warbler

Chestnut-sided Warblers are now common migrants in the Northfield area. Surprisingly, in Audubon's time, naturalists almost never reported seeing this species. The populations of Chestnut-sided Warblers have greatly increased because they breed in scrubby secondary growth--the habitat that often results from regenerating logging clear cuts or from fallow fields in abandoned farmland. Byers et al. (2013) write, "the Chestnut-sided Warbler is one of the few Neotropical migrants that has benefited dramatically from human activities on the North American continent." (See also my previous post on this species.)

Scarlet Tanager

When John Holden called me on Tuesday and said that he had Scarlet Tanagers in his yard, I think he was disappointed in my relative lack of enthusiasm  I had just checked the species off on my year list. I did not know he meant he had Scarlet Tanagers at his bird feeders! Our bird trip last Wednesday was subverted as I took photos of his birds, both the male above and the female below. The birds fed on both suet (as in the third photo) and seed. The female in these photos seems to have black wings (which would make it a second-year male), but this dark color is an artifact of the photograph. The wings were actually greenish.

Scarlet Tanagers breed in the eastern United States and southeastern Canada and winter in northeastern South America. We often observed this species in the winter along the Napo River in the Ecuadorian Amazon Basin. But the biggest threat to the species is not its long-distance migration, but, rather, forest-fragmentation. As forests are felled for development and agriculture, small forest patches leave tanagers susceptable to cowbird parasitism and predators (Mobray 1999). 

As I wrote this post, Erika and I banded a another tanager, this time at our home. Try as I might, I just can’t get the camera to reproduce the intensity of this tanager’s scarlet. This last photo comes close, although I do not know from whence comes the yellow. Perhaps the yellow comes from the base of the contour feathers. At least you can easily see the “toothed” nature of the bill.