Sam Crowe on August 21st, 2017

While many birders flock to air conditioned comfort during August, many shorebird species will start their southern migration during the month. According to the Stanford web site more than 20 million shorebirds migrate through the United States to the Arctic each year. The web page includes the following information.

Whimbrel

Whimbrel

“As a group, shorebirds undertake some of the most spectacular of long-distance migrations of any North American birds. Nearly two-thirds of the species that breed in North America journey from their arctic nesting grounds to winter in Central and South America, and then return to the Arctic the following spring. Many species traverse more than 15,000 miles in this annual circuit. Some fly at altitudes exceeding 10,000 feet and achieve cruising speeds approaching 50 mph. From sightings of marked individuals, we know that at least some birds on nonstop flights cover nearly 2,000 miles in less than two days. Hudsonian Godwits may fly 8,000 miles nonstop between breeding and wintering areas, unless brief stopovers are made at as-yet-undiscovered spots somewhere in South America. The surprising migration feats of Sanderlings were discovered only recently by ornithologist Pete Myers. Their hitherto unsuspected circumnavigation of the Americas each year follows a route east across the top of North America and down the Atlantic coast in the autumn to their wintering grounds in Chile and Peru, and back north in the spring through the western United States to their arctic breeding grounds.”

It has been know for several years that some birds see well in the UV range and that UV markings on windows, while not visible to humans, can be detected by birds and offer protection from window collisions. The UV effect might not be ideal for evey situation, as reported from this excerpt from research posted on the PeerJ web site.

“Glass windows cause more bird fatalities than one might think (Banks, 1976). Being optimized for flight, birds are lightly built and collisions with large obstacles often result in serious injury or death. Because the glass reflects the landscape outside (Fig. 1) or offers a more or less unobstructed view of items behind the window as well as the landscape on another side of a building, it may trick birds into believing that the window is an available flight path. As a consequence, the world-wide avian death toll from window collisions reaches billions each year, according to recent estimates (Drewitt & Langston, 2008; Klem Jr, 2009a).

The means to prevent avian window collisions include nets, screens or grilles that are placed at a safe distance in front of windows or densely spaced, visible markings applied to the glass directly. Albeit effective (Rössler, Laube & Weihs, 2007) these solutions diminish the aesthetic value of having window glass in buildings, and will impair the view of the scene outside. Since it was discovered that diurnal birds can see ultraviolet radiation (Huth & Burkhardt, 1972; Wright, 1972) to which humans are blind, reflective or absorbing ultraviolet markings on window glass have been proposed and tested to make birds notice the surface while the marking remains invisible to human observers. However, this seemingly elegant solution to the problem has had varying success (see Haupt, 2011). On the one hand, ultraviolet absorbing stripes on a window with narrow (5–10 cm) spacing have proven almost as effective as covering virtually the whole window with human-visible markings (Klem Jr, 2009b). On the other hand, field tests of commercially available UV-patterned glass have, under see-through conditions, shown an increased likelihood of window collisions compared to ordinary window panes (Klem Jr & Saenger, 2013).”

From the Friends of the Wild Whoopers web site.

“The remote muskeg of the taiga in Wood Buffalo National Park in Alberta, and its surrounding environs have long been the last holdout for nesting Whooping Cranes on the continent. This wild population, discovered in 1954 by Robert Porter Allen, is the population that migrates annually to the area of Aransas National Wildlife Refuge on the Texas coast. All other experimental Whooping Crane populations have derived – one way or another – from the eggs of birds from this Canadian breeding population.

This year, in a report issued by Mike Keizer, External Manager at the Wood Buffalo National Park, a record number of Whooping Cranes were found in the Park during the recent 2017 nesting survey run by Parks Canada and Environment and Climate Change Canada. This season’s survey found a record 98 nests, an increase of 16 over the previous record of 82 nests set in 2014. Another aerial survey will be run next month to determine the number of fledged colts, as the young cranes are called. This is exciting news and important information for crane fans everywhere.”

Visit the Friends of the Wild Whoopers web site for updates on wild Whoopers nesting in Canada and the Wood Buffalo National Park breeding season.

Sam Crowe on July 16th, 2017

I found this article on the Black-capped Vireo and cowbird predation especially interesting as several years ago I had the opportunity to spend the day at Fort Hood in central Texas, where much of this study took place. The fine folks from the Nature Conservancy were studying both the Black-capped Vireo and Golden-cheeked Warbler and working on conservation of the these two endangered species. Black-capped Vireos prefer to nest in disturbed areas and it was interesting to learn that a popular nesting location was located where training ordinances were detonated.

black-capped-vireo

Black-capped Vireo. © Greg Lavaty

From Avian Conservation & Ecology
Lauren E Walker, School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
John M Marzluff, School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA

Abstract: Full article here.
Breeding birds vocalize to find mates and establish and defend territories, but these same critical communications may also attract predators or brood parasites, placing birds in a cruel bind. Although vigilant birds may better maintain social relationships with mates and neighbors through frequent vocalizations, reticent birds may reduce risk to their nests by being relatively quiet and making infrequent vocalizations. Selection for vocalization patterns that minimize brood parasitism might be particularly strong for birds that are unable to fledge both their own young and the parasite. Temporal plasticity in the frequency of vocalizations near nests, however, may allow birds to balance trade-offs and optimize nest-defense strategies. The Black-capped Vireo (Vireo atricapilla) is an endangered songbird that faces intensive brood parasitism in areas where Brown-headed Cowbirds (Molothrus ater) are present. Vireo nests that produce cowbird fledglings always fail to fledge vireo young. We recorded vocalizations at vireo nests across three nesting stages (building, laying, and early incubation) and three periods of the day (morning, midday, and evening) and compared vocalization frequency with eventual depredation or parasitism fate as well as local cowbird density to test two hypotheses. The predator-attraction hypothesis predicts that predators will be attracted by frequent vocalizations, whereas cowbirds will parasitize nests with relatively quiet parents and less predation risk; thus, vireos will experience trade-offs between reticence and vigilance in mediating specific risks. The parasite-assessment hypothesis predicts that vireos will become more secretive as local cowbird densities increase. Vireo vocalization response to nest predation and parasitism risk interacted with nest stage, and we found little evidence of risk mediation through vocalizations except during the building stage. Vireos, however, did benefit overall by optimizing temporal patterns in vocalizations. Vireo nests were less likely to be depredated or parasitized if males vocalized most during laying and least during the middle of the day. Birds vocalized more during the midday and less during the laying period when local cowbird densities were higher, however, perhaps demonstrating limited plasticity in social communication.

Sam Crowe on July 9th, 2017

Zoologists at the University of Cambridge filmed a group of Mallards hunting other birds on a reservoir in Romania.

mallard eating redstart

Two fledglings – a grey wagtail and a black redstart – were chased and swallowed when they landed in the water.

Mallards normally feed on seeds, plants and insects. Small fish are occasionally on the menu but consumption of larger vertebrates by Mallards is quite rare.

The BBC web site has more on the story and images of the predator female Mallards.

Sam Crowe on July 4th, 2017

A new parrot species has been identified from the Yucatán Peninsula: The Blue-winged Amazon.

I had no idea there were remote parts of the Yucatán Peninsula but apparently there are. The next time I make a trip to Cancun think I’ll wonder inland a little bit.

In 2014, during a visit to one of the remote locations of the Yucatán Peninsula in Mexico, ornithologist Dr. Miguel A. Gómez Garza discovered a new species of parrot, which has been named the Blue-winged Amazon (Amazona gomezgarzai). The new species has a distinctive call and distinctive color pattern.

A complete report on the discovery and study of the new species is available on the PeerJ web site.

Blue-winged Amazon

Sam Crowe on June 26th, 2017

The speculum is a patch of often iridescent color on the secondary feathers of many duck species.  It is often seen as a bright patch of color on the rear of the wing when the wing is spread during flight or when the bird is stretching.  The color and size of the speculum varies by species.

The speculum may also be edged with white or other colors.

The leading edge of the wings of several duck species can also be very colorful and a nice aid to identification.  Here are some examples of very distinctive speculums and other wing colors.

The underside of the wings, referred to as the wing linings, are usually very plain in appearance.

Blue-winged Teal
It is easy to see where this species obtained its name.  Note the speculum is green.  Compare the colored parts of the wing to the the image that follows.

blue-winged teal in flight

duck wing pattern

Northern Shoveler
The male Northern Shoveler wing pattern is very similar to the Blue-winged Teal.  The distinctive large bill of the shoveler is clearly noticeable.

northern shoveler in flight

Gadwall
The Gadwall has a very different wing pattern. The white speculum is very visible in flight.

gadwall in flight

Mallard
The Mallard has a very distinctive speculum that can appear blue to purple, depending on the light. The speculum is edged above and below with white.

mallard in flight

Sam Crowe on June 18th, 2017

What is the only North American (U.S. and Canada) songbird that breeds exclusively in Canada?  It is one of our most beautiful, and one of my favorite sparrows – the Harris’s Sparrow.

The Harris’s Sparrow nests primarily in the boreal-tundra transition of the Northwest Territories, Nunavut, and the northernmost parts of Saskatchewan, Manitoba, and Ontario.

The species is primarily monitored on its wintering grounds in the U.S., where numbers have declined by nearly 60% since 1980. The Harris’s Sparrow was assigned the status of Special Concern on the basis of this trend, and concerns of ongoing threats such as habitat conversion, cat predation, and climate change.

Plumages vary. Harris’s Sparrows have dominance hierarchies in winter, with body size and the extent of black feathering on the bib contributing to a bird’s position in the hierarchy.  The winter range is limited to the central United States.

Sam Crowe on June 4th, 2017

This little bit if happy news is from The Birding Community E-Bulletin.

In a refreshing move of bipartisanship, Rep. Mike Quigley (D-IL) and Rep. Morgan Griffith (R-VA) recently introduced the Federal Bird-Safe Buildings Act. The bill (H.R. 2542) is designed to amend title 40 of the United States Code to direct the General Services Administration (GSA) to incorporate bird-safe building materials and design features into public Federal buildings.

It is believed that as many as a billion birds a year currently die in collisions with buildings in North America alone. Achieving city-by-city, county-by-county, or even state-by-state compliance in assuring bird-safe design and seasonal lighting is an excellent conservation approach, and so is asking for state-government, company-wide, and now Federal policy to engage in this endeavor.

The bill calls for each public building constructed, acquired, or significantly altered by the General Services Administration to incorporate, to the maximum extent possible, bird-safe building materials and design features. Many bird-friendly design techniques – such as installing screens or grilles on windows, and minimizing the use of glass on lower floors – are already used in some federal buildings to control heat and light or building security. Where practicable, this new legislation would require GSA to take similar actions on existing buildings.

“By pursuing cost-neutral, responsible, and realistic solutions we can play an important role in preserving the intrinsic, cultural, and ecological value birds bring to our society,” Rep. Quigley said. “This bill will put an emphasis on constructing buildings with bird-safe materials and design features, which in turn will help eradicate unnecessary bird deaths caused by collisions with glass.”

You can read a statement by Rep. Quigley here:

And also see comments from the American Bird Conservancy here:

Audubon has launched a pilot program called Climate Watch. The plan is to use bluebirds and nuthatch observations to validate Audubon’s predictions on how birds’ territory ranges will shift in response to a changing climate.

Audubon released its Birds and Climate Change Report in 2014. It used Christmas Bird Count and Breeding Bird Survey data to model how different bird species’ preferred climatic conditions, like temperature and rainfall, may shift in response to climate change.  Although based on data the models were educated guesses.

By studying common, easy-to-identify birds the program hopes to establish base-line information and then track changes over time.

Many models that attempt to predict changes in territory rely on the fundamental assumption that a species’ preferred climatic conditions won’t change. That is, birds will search for the climate they’re used to rather than to trying to adjust to the climate change in their historic range. Climate Watch allows scientists to test this underlying assumption, in addition to seeing whether birds match the model’s predictions.

Birds included in the study include all three bluebird species plus White-breasted, Red-breasted, Brown-headed and Pygmy Nuthatches.

Mountain Bluebird

Mountain Bluebird

Details available on the Audubon web site:
Information on the participating in the Climate Watch Program.

The Climate Change Report with Audubon’s findings, their implications, and how to interpret the data is available in both a quick overview video and detailed information.

Audubon’s climate change news and programs.

Warmer weather brings noticeable changes in the Great Backyard Bird Count