Swifts and swallows in North America, new study

This video from the USA says about itself:

Martin and Tree Swallow nest cameras

Look inside bird nests in Kentucky as of May 18, 2015. First part is a Purple Martin, last part is a Tree Swallow. Watch momma Tree Swallow feed her featherless, pink babies yummy bugs!

From Ecography journal:

Differences in spatial synchrony and interspecific concordance inform guild-level population trends for aerial insectivorous birds

3 NOV 2015


Many animal species exhibit spatiotemporal synchrony in population fluctuations, which may provide crucial information about ecological processes driving population change.

We examined spatial synchrony and concordance among population trajectories of five aerial insectivorous bird species: chimney swift Chaetura pelagica, purple martin Progne subis, barn swallow Hirundo rustica, tree swallow Tachycineta bicolor, and northern rough-winged swallow Stelgidopteryx serripennis. Aerial insectivores have undergone severe guild-wide declines that were considered more prevalent in northeastern North America.

Here, we addressed four general questions including spatial synchrony within species, spatial concordance among species, frequency of declining trends among species, and geographic location of declining trends. We used dynamic factor analysis to identify large-scale common trends underlying stratum-specific annual indices for each species, representing population trajectories shared by spatially synchronous populations, from 46 yr of North American Breeding Bird Survey data. Indices were derived from Bayesian hierarchical models with continuous autoregressive spatial structures. Stratum-level spatial concordance among species was assessed using cross-correlation analysis.

Probability of long-term declining trends was compared among species using Bayesian generalized linear models. Chimney swifts exhibited declining trends throughout North America, with less severe declines through the industrialized Mid-Atlantic and Great Lakes regions. Northern rough-winged swallows exhibited declining trends throughout the west. Spatial concordance among species was limited, the proportion of declining trends varied among species, and contrary to previous reports, declining trends were not more prevalent in the northeast. Purple martins, barn swallows, and tree swallows exhibited synchrony across smaller spatial scales. The extensive within-species synchrony and limited concordance suggest that population trajectories of these aerial insectivores are responding to large-scale but complex and species- and region-specific environmental conditions (e.g. climate, land use). A single driver of trends for aerial insectivores as a guild appears unlikely.

Ruddy turnstone on beach, video

This video from North America says about itself:

Ruddy Turnstone foraging on beach

5 June 2015

Ruddy Turnstones are a familiar, medium-sized shorebird of beaches on both coasts. In breeding plumage, their bold, contrasting plumage is almost cartoonish, and this species also feeds very actively, flipping over rocks and shells with its bill to search for invertebrates as it marches along the shoreline.

Sandhill cranes flock, video

This video from the USA says about itself:

Flock of Sandhill Cranes

5 June 2015

One of two crane species in North America, and by far the most common and frequently encountered, the Sandhill Crane is a large, graceful, long-necked bird of open prairies and wetlands. This species gathers in large flocks outside of the breeding season, and the collective cacophony of their bugling calls can be deafening. Their large size, red crown, and slender black bill help distinguish the Sandhill Crane from any heron or egret species.

Orange-crowned warbler feeding, video

This video from the USA says about itself:

Orange-crowned Warbler feeding on the ground

22 July 2015

Orange-crowned Warblers are fairly plain, yellow-green warblers with sharply pointed bills. The yellow feathers under the tail help distinguish this bird from the similar Tennessee Warbler. These birds can be seen in shrubs and woods across North America, but are more common in the West than in the East.

Ovenbird gathers nesting material, video

This video from the USA says about itself:

22 July 2015

Ovenbirds have the general coloration of a thrush, but they are a species of warbler. They breed in rich woodlands, where they spend much of their time walking on the forest floor.

Pied-billed grebe video

This video from the USA says about itself:

22 July 2015

Pied-billed Grebes are very small waterbirds common across much of North America. Though they act like ducks, they have the small body, slender neck, and straight non-flattened bill of a grebe. They frequently dive for food or for safety and can spend surprisingly long periods underwater.

Pine warbler sings, video

This video from the USA says about itself:

Pine Warbler singing

22 July 2015

Pine Warblers are bright-yellow songbirds with a fairly large bill for a warbler. They are common in eastern North America and true to their name are most frequently seen in pine trees. The song is an evenly spaced, level musical trill.