Blackpoll warbler migration in America, new research


This video from New York City says about itself:

Several male blackpoll warblers (Setophaga striata) are shown in Central Park on their migration to their northern breeding grounds. The blackpoll warbler spends the winter in northern South America and migrates to Alaska, Canada, and small portions of the northeastern United States to breed. It is a common species, and it is assessed as being of least concern by the IUCN Red List of Threatened Species.

This video was recorded on May 13, 14, and 17, 2014 in Central Park, New York City.

From Science Daily:

Tiny songbird discovered to migrate non-stop, 1,500 miles over the Atlantic

Date: March 31, 2015

Source: University of Massachusetts at Amherst

Summary: For the first time biologists report ‘irrefutable evidence’ that tiny blackpoll warblers complete a nonstop flight from about 1,410 to 1,721 miles (2,270 to 2,770 km) in just two to three days. For this work the scientists fitted geolocator packs on 20 birds in Vermont and 20 more in Nova Scotia. They were able to recapture three birds from the Vermont group and two from the Nova Scotia group for analyses.

For more than 50 years, scientists had tantalizing clues suggesting that a tiny, boreal forest songbird known as the blackpoll warbler departs each fall from New England and eastern Canada to migrate nonstop in a direct line over the Atlantic Ocean toward South America, but proof was hard to come by.

Now, for the first time an international team of biologists report “irrefutable evidence” that the birds complete a nonstop flight ranging from about 1,410 to 1,721 miles (2,270 to 2,770 km) in just two to three days, making landfall somewhere in Puerto Rico, Cuba and the islands known as the Greater Antilles, from there going on to northern Venezuela and Columbia. Details of their study, which used light-level, or solar, geolocators, appear in the current issue of Biology Letters.

First author Bill DeLuca, an environmental conservation research fellow at the University of Massachusetts Amherst, with colleagues at the University of Guelph, Ontario, the Vermont Center for Ecostudies and other institutions, says, “For small songbirds, we are only just now beginning to understand the migratory routes that connect temperate breeding grounds to tropical wintering areas. We’re really excited to report that this is one of the longest nonstop overwater flights ever recorded for a songbird, and finally confirms what has long been believed to be one of the most extraordinary migratory feats on the planet.”

While other birds, such as albatrosses, sandpipers and gulls are known for trans-oceanic flights, the blackpoll warbler is a forest dweller that migrates boldly where few of its relatives dare to travel. Most migratory songbirds that winter in South America take a less risky, continental route south through Mexico and Central America, the authors note. A water landing would be fatal to a warbler.

In the recent past, DeLuca explains, geolocators have been too large and heavy for use in studying songbird migration and the tiny blackpoll warbler, at around half an ounce (12 grams) or about as much as 12 business cards, was too small to carry even the smallest of traditional tracking instruments. Scientists had only ground observations and radar as tools.

But with recent advances in geolocator technology, they have become lighter and smaller. For this work, the researchers harnessed miniaturized geolocators about the size of a dime and weighing only 0.5g to the birds’ lower backs like a tiny backpack. By retrieving these when the warblers returned to Canada and Vermont the following spring, then analyzing the data, DeLuca and colleagues could trace their migration routes.

For this work the scientists fitted geolocator packs on 20 birds in Vermont and 20 more in Nova Scotia. They were able to recapture three birds from the Vermont group and two from the Nova Scotia group for analyses.

So-called light-level geolocators use solar geolocation, a method used for centuries by mariners and explorers. It is based on the fact that day length varies with latitude while time of solar noon varies with longitude. So all the instrument needs to do is record the date and length of daylight, from which daily locations can then be inferred once the geolocator is recaptured. “When we accessed the locators, we saw the blackpolls’ journey was indeed directly over the Atlantic. The distances travelled ranged from 2,270 to 2,770 kilometers,” DeLuca says.

To prepare for the flight, the birds build up their fat stores, explains Canadian team leader Ryan Norris of the University of Guelph. “They eat as much as possible, in some cases doubling their body mass in fat so they can fly without needing food or water. For blackpolls, they don’t have the option of failing or coming up a bit short. It’s a fly-or-die journey that requires so much energy.”

He adds, “These birds come back every spring very close to the same place they used in the previous breeding season, so with any luck you can catch them again. Of course there is high mortality among migrating songbirds on such a long journey, we believe only about half return.”

Chris Rimmer, an ornithologist at the Vermont Center for Ecostudies notes, “We’ve only sampled this tiny part of their breeding range. We don’t know what birds from Alaska do, for example. This may be one of the most abundant warblers in North America, but little is known about its distribution or ecology on the wintering grounds in Venezuela and the Amazon. However, there is no longer any doubt that the blackpoll undertakes one of the most audacious migrations of any bird on earth.”

DeLuca says, “It was pretty thrilling to get the return birds back, because their migratory feat in itself is on the brink of impossibility. We worried that stacking one more tiny card against their success might result in them being unable to complete the migration. Many migratory songbirds, blackpolls included, are experiencing alarming population declines for a variety of reasons, if we can learn more about where these birds spend their time, particularly during the nonbreeding season, we can begin to examine and address what might be causing the declines.”

As for why the blackpoll undertakes such a perilous journey while other species follow a longer but safer coastal route, the authors say that because migration is the most perilous part of a songbird’s year, it may make sense to get it over with as quickly as possible. However, this and other questions remain to be studied.

Other researchers on the team besides those from UMass Amherst, the University of Guelph and the Vermont Center for Ecostudies, were from the Smithsonian Conservation Biology Institute, Acadia University, Bird Studies Canada and the University of Exeter, U.K. Each contributed to funding the study.

Light-level geolocators reveal that Veeries instinctively follow the shortest possible #migration path: here.

Rotate a warbler in 3D, distinguish similar-sounding songs with spectrograms, or identify a warbler using clues from plumage and song at the same time. With this new app from The Warbler Guide authors Tom Stephenson and Scott Whittle, ID tips leap off the page onto your mobile device in a whole new way. Read our review.

Male, female wrens singing duets


This video says about itself:

Plain-Tailed Wrens‘ Songs

7 November 2011

Long-married human couples may finish each others’ sentences, but the plain-tailed wrens of the Andes take things a step further. Male and female wrens sing intimate duets in which they alternate syllables so quickly it sounds like a single bird is singing. New research shows that the brains of both the male and female wrens actually process the entire duet, not just each bird’s own contribution.

Dr. Fortune plays some examples of plain-tailed wrens’ songs.

This video about plain-tailed wrens says about itself:

3 November 2011

Wrens’ Brains Are Wired for Duets

And this video is the sequel.

Plain-tailed wrens are not the only wrens singing duets. So do other wren species, especially in tropical countries; eg, band-backed wrens.

The plant family Corsiaceae, new research


This video is called Liliaceae plant family, description, examples, info.

From the Journal of Biogeography:

Ancient Gondwana break-up explains the distribution of the mycoheterotrophic family Corsiaceae (Liliales)

19 FEB 2015

Abstract

Aim

Many plant families have a disjunct distribution across the southern Pacific Ocean, including the mycoheterotrophic family Corsiaceae, which provides a prime example of this biogeographical pattern. A better grasp of the family’s evolutionary relationships is needed to understand its historical biogeography. We therefore aimed to (1) test the uncertain monophyly of Corsiaceae, (2) define its phylogenetic position, and (3) estimate divergence times for the family, allowing us to assess whether the distribution of the family is the result of vicariance.

Location

Southern South America and Australasia.

Methods

We analysed various combinations of mitochondrial and nuclear data to address the monophyly, phylogenetic position and age of Corsiaceae. To test its monophyly, we used a three-locus data set including most monocot orders, and to infer its exact phylogenetic position, we used a five-locus extended data set. We corroborated these findings using an independent plastome dataset. We then used a two-locus dataset with taxa from all monocot orders, and a three-locus dataset containing only taxa of Liliales, to estimate divergence times using a fossil-calibrated uncorrelated lognormal relaxed-clock approach.

Results

Corsiaceae is a monophyletic family and the sister group of Campynemataceae. This clade is the sister group of all other Liliales. The crown age of Corsiaceae is estimated to be 53 Ma (95% confidence interval 30–76 Ma).

Main conclusions

Corsiaceae is an ancient family of mycoheterotrophic plants, whose crown age overlaps with the plate-tectonic split of Gondwana, consistent with a vicariance-based explanation for its current distribution.

See also here.

South American hummingbird has improved Internet page


This is a video about a little hermit, a hummingbird species from the north of South America.

New on Neotropical Birds Online: completed account for Little Hermit (Phaethornis longuemareus) by Linh Huynh: here.

North American songbird southward migration, new research


This video from the USA is called Act for Songbirds – Help Save Threatened Migratory Birds.

From the Journal of Field Ornithology in Canada:

Connecting breeding and wintering grounds of Neotropical migrant songbirds using stable hydrogen isotopes: a call for an isotopic atlas of migratory connectivity

Volume 85, Issue 3, pages 237–257, September 2014

ABSTRACT

There is an overdue and urgent need to establish patterns of migratory connectivity linking breeding grounds, stopover sites, and wintering grounds of migratory birds. Such information allows more effective application of conservation efforts by applying focused actions along movement trajectories at the population level. Stable isotope methods, especially those using stable hydrogen isotope abundance in feathers (δ2Hf) combined with Bayesian assignment techniques incorporating prior information such as relative abundance of breeding birds, now provide a fast and reliable means of establishing migratory connectivity, especially for Neotropical migrants that breed in North America and molt prior to fall migration.

Here we demonstrate how opportunistic sampling of feathers of 30 species of wintering birds in Cuba, Venezuela, Guatemala, Puerto Rico, and Mexico, regions that have typically been poorly sampled for estimating migratory connectivity, can be assigned to breeding areas in North America through both advanced spatial assignment to probability surfaces and through simpler map lookup approaches. Incorporating relative abundance information from the North American Breeding Bird Survey in our Bayesian assignment models generally resulted in a reduction in potential assignment areas on breeding grounds.

However, additional tools to constrain longitude such as DNA markers or other isotopes would be desirable for establishing breeding or molt origins of species with broad longitudinal distributions. The isotope approach could act as a rapid means of establishing basic patterns of migratory connectivity across numerous species and populations.

We propose a large-scale coordinated sampling effort on the wintering grounds to establish an isotopic atlas of migratory connectivity for North American Neotropical migrants and suggest that isotopic variance be considered as a valuable metric to quantify migratory connectivity. This initiative could then act as a strategic template to guide further efforts involving stable isotopes, light-sensitive geolocators, and other technologies.

American tanagers’ colours and songs, new study


This video is called Colombia Tanagers [various species].

From Wildlife Extra:

Study dispels Darwin’s theory to prove birds can have it all

Despite popular belief birds can have a brilliant plumage, a virtuosic singing chirp and an intricate dance routine say scientists.

The author of a new study, Nick Mason, from the the Cornell Lab of Ornithology in New York state, challenged the long-held notion, first proposed by Charles Darwin, that for a bird species to excel in one area it must give up its edge in another.

For example, male northern cardinals are a dazzling scarlet, but sing a fairly simple whistle, whereas the dull brown House Wren sings one of the most complicated songs in nature.

Mason and his colleagues tested the theory by examining a very large family of songbirds from Central and South America, the tanagers.

This group consists of 371 species and included some of the most spectacularly colourful birds in the world such as the paradise tanager as well as the more drab birds, such the black-bellied seedeater. The group also includes both accomplished and weak songsters alike.

“If there were going to be any group of birds at all that would show this trade-off, the tanagers would be a very good candidate, because there’s all this variation in song and plumage complexity,” Mason said.

“But when we dived into it and did some rigorous statistics, it turns out that there is no overall trend. Tanagers can be drab and plain-sounding, or colourful and musical, or or anything in between.”

It’s still possible that trade-offs take place at the level of genus, Mason said, or that they influence species relatively fleetingly as evolutionary pressures appear and disappear.

But as a broad effect on an entire family of birds, a voice–plumage trade off doesn’t seem to exist. One possibility is that the resources needed to develop fancy plumage are different from the ones required for complex songs, freeing tanagers to invest in both forms of showiness simultaneously.

United States songbirds migrate with the wind, new study


This video from Canada says about itself:

Indigo bunting, Blackburnian warbler, stop on migration at my bird feeder

14 May 2013

My first sighting of Indigo bunting, Blackburnian Warbler, photos and video on their way North, Woodslee, Ontario.

From Wildlife Extra:

US songbirds are found to migrate with the wind

Millions of tiny songbirds, many weighing less than an ounce, migrate thousands of miles from North America to Central and South America each year. How they do it has been somewhat of a mystery, but now scientists have discovered how far they take advantage of prevailing wind patterns to save calories.

“Most of what we’ve known about migration routes comes from ducks and geese,” said Frank La Sorte, a Cornell Lab of Ornithology research associate and lead author of the paper in the Journal of Biogeography. “But terrestrial birds are much smaller and they aren’t reliant on the same kinds of habitats. There really isn’t a narrow migration path for them, and they aren’t necessarily in the same place in spring and fall.”

The findings from this study are important as they may help refine ideas about how and where to plan for conservation along migratory pathways.

“All these species migrate at night, at high altitudes, where we can’t see them,” La Sorte said. “But when the sun comes up in the morning they have to find somewhere to land. So any new knowledge about where they’re travelling is valuable to conservation planners.”

For years US scientists assumed songbirds followed the same well-defined “flyways” that ducks, geese, and shorebirds used to travel up and down the continent. There is one known wildfowl flyway along each coast, one up the Mississippi River valley, and one in the centre of the country. Those flyways were marked out from studies which compiled data from recoveries of birds with leg rings and records kept by hunters, but those methods don’t work for small songbirds that migrate at night.

The new work solved this problem with a fresh approach using crowd-sourced data submitted to the Cornell Lab’s eBird project between 2004 and 2011. The researchers analysed thousands of people’s sightings to develop, for each of 93 species, an aggregate picture of where a species is during spring and autumn migration. Although they weren’t tracking individual birds, collective sightings gave them an indication of how the species were migrating. They then used computer models to sort species with similar movement patterns into groups and compared migration routes with seasonal patterns of prevailing winds at night.

The study revealed that most US land birds fit into three main groups: a western one of 31 species, a central group of 17 species, and an eastern of 45 species. Examples of each group include the black-throated gray warbler, the clay-coloured sparrow, and the American redstart, respectively. The researchers noted that the flyways for these are much more spread out across the continent than those of wildfowl, and routes in the central and eastern groups overlap considerably.

The analysis also revealed that many more land birds than previously realised follow different routes through America in spring and autumn — particularly in the East, where many species cross the Gulf of Mexico in a single overnight flight.

Unlike wildfowl, which migrate north and south along the same relatively narrow routes, rather like lorries on a motorway, songbirds are more like passenger cars touring back roads. They are less tied to a single wetland habitat, so they can fan out. By shifting routes, birds take advantage of stronger tailwinds in spring and less severe headwinds in autumn. Tailwinds represent a huge advantage for small birds heading north to their breeding grounds, while finding weaker headwinds allows southbound birds to make the best of a bad situation.

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