Fish warn others chemically about dangers


This june 2013 video is called Fathead minnows in my pond.

From the University of Saskatchewan in Canada:

Fish under threat release chemicals to warn others of danger

April 18, 2019

Fish warn each other about danger by releasing chemicals into the water as a signal, research by the University of Saskatchewan (USask) has found.

The USask researchers discovered that wild fish release chemicals called ‘disturbance cues’ to signal to other fish about nearby dangers, such as predators.

The findings may have implications for fish conservation efforts across the globe.

“Disturbance cues may help to explain why some fish populations crash after they decline past a certain point,” said Kevin Bairos-Novak, a graduate student member of the research team.

While researchers have been aware that fish release chemicals into the water for 30 years, this is the first time their use has been studied.

The findings, involving researchers from the USask biology department and the Western College of Veterinary Medicine, are published in the Journal of Animal Ecology.

Fish signaled most when in the presence of familiar fish, but signaled far less or not at all when in the presence of strangers, or when on their own.

The signals provoked a ‘fright response’ in fish they knew, including freezing, dashing about and then shoaling tightly together. Fish use this behavior to defend themselves against predators.

“When minnows

The research is about fathead minnows. They live in North America.

were present alongside familiar minnows, they were much more likely to produce signals that initiated close grouping of nearby fish, a strategy used to avoid being eaten by predators,” said Bairos-Novak, who is now at James Cook University, Australia.

Disturbance cues are voluntarily released by prey after being chased, startled or stressed by predators.

One of the main constituents of the signal is urea, found in fish urine.

Fathead minnows, caught at a lake, were placed in groups with familiar fish, unfamiliar fish or as isolated individuals. The research team then simulated a predator chase. The fish responded by shoaling, freezing and dashing when they received a signal from a group they knew. But they did not take significant defensive action when receiving cues from unfamiliar fish or isolated minnows.

Disturbance cues are voluntarily released by prey after being chased, startled or stressed by predators.

“It is exciting to discover a new signaling pathway in animals,” said Maud Ferrari, Bairos-Novak’s supervisor and a behavioural ecologist in the veterinary college’s Department of Veterinary Biomedical Sciences. “We found that fish are able to manipulate the behaviour of other individuals nearby by issuing a signal.”

The research was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).

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Climate change theatens North American sparrows


This 24 June 2011 video from the USA says about itself:

Seaside Sparrows in Connecticut Saltmarsh. ©JimZipp2011; following New Moon high tides that flooded out all nests.

From Oxford University Press USA:

Climate change threatens endangered sparrows

April 16, 2019

A new study in The Condor: Ornithological Applications finds that some sparrow species will go extinct within the century due to climate change.

Seaside (Ammospiza maritima) and saltmarsh (A. caudacuta) sparrows are closely related species and among only five bird species that are almost completely restricted to coastal salt marshes for their entire life. These sparrows’ nests are predominantly destroyed by predators or flooding.

Salt marshes are globally limited to about 30,000 square miles (45,000 square km), with one-third of the total on North American coasts. Of the 25 species or subspecies limited to tidal wetlands worldwide, 15 are restricted to the US Atlantic and Gulf coasts. Given rapid climate changes and other threats to salt marsh ecosystems, many of these species are in serious danger.

The global breeding range of the saltmarsh sparrow extends from Virginia to Maine, with a population estimate of 60,000 birds. Sea-level rise can negatively impact breeding seaside and saltmarsh sparrows by reducing the amount of available habitat, and by increasing nest flooding rates. Furthermore, the high human population densities of Mid-Atlantic states also make it difficult for sparrows to thrive in the region.

This study aimed to estimate population trajectories for seaside and saltmarsh sparrows within Edwin B. Forsythe National Wildlife Refuge in New Jersey, identify the primary drivers of those trajectories, and explore potential management strategies to prevent declines.

The researchers found that seaside sparrows persisted under a 1 ft (0.35 m) rise in sea level scenario and also under a sea level rise of almost 2.5 ft (0.75 m). Saltmarsh sparrows survived in neither scenario. With a 1 ft rise in sea level, the seaside sparrow population experienced a compound decline of .35% a year. Under the 2.5 ft sea level rise scenario, this decline increased to .56% a year. The saltmarsh sparrow median time to quasi-extinction was 20 years under both scenarios.

The results indicated that seaside sparrows are likely to persist, while saltmarsh sparrows are likely to become locally extinct in the next 30 years.

“Given the projected increases in sea level over the next few decades and threats from predators, we will need to implement timely and creative actions to avoid extinction of saltmarsh sparrows,” said the paper’s lead author, Samuel Griffith Roberts.

Protecting American migratory birds


This March 2017 video from the USA says about itself:

Bird Migration in North America

An overview on how and why birds migrate, including species such as the Yellow Warbler and the Woodthrush, as well as challenges migratory birds face today. This educational video was completed for ‘Birds Ecosystems and People’ at Allegheny College.

From Cornell University in the USA:

Scientists use eBird data to propose optimal bird conservation plan

The goal is to conserve habitat and protect migratory birds

April 15, 2019

A new paper published today in the journal Nature Communications shows a blueprint for conserving enough habitat to protect the populations of almost one-third of the warblers, orioles, tanagers, and other birds that migrate among the Americas throughout the year.

For the research, an international team of scientists used the Cornell Lab of Ornithology’s global citizen science database, eBird, to calculate how to sufficiently conserve habitat across the Western Hemisphere for all the habitats these birds use throughout their annual cycle of breeding, migration, and overwintering. The study provides planners with guidance on the locations and amounts of land that must be conserved for 30 percent of the global populations for each of 117 Neotropical migratory bird species.

More than a third of Neotropical migratory birds are suffering population declines, yet a 2015 global assessment found that only 9 percent of migratory bird species have adequate habitat protection across their yearly ranges to protect their populations. Conservation of migratory birds has historically been difficult, partly because they require habitat across continents and conservation efforts have been challenged by limited knowledge of their abundance and distribution over their vast ranges and throughout the year.

“We are excited to be the first to use a data-driven approach that identifies the most critical places for bird conservation across breeding, overwintering, and migratory stopover areas throughout the Western Hemisphere. In doing so, we provide guidance on where, when, and what type of habitat should be conserved to sustain populations,” said Richard Schuster, Liber Ero Postdoctoral Fellow at Carleton University, and lead author on the Nature Communications paper. “This is a vital step if conservationists are to make the best use of limited resources and address the most critical problems at a hemispheric scale.”

The team’s analysis found that conservation strategies were most efficient when they incorporated working lands, such as agriculture or forestry, rather than exclusively focusing on areas with limited human impacts (i.e., intact or undisturbed landscapes). The importance of shared-use or working landscapes to migratory birds underscores how strategic conservation can accommodate both human livelihoods and biodiversity. The research also found that efficiency was greatest — requiring 56 percent less land area — when planning across the entire year in full, rather than separately by week.

“Efforts to conserve migratory species have traditionally focused on single species and emphasized breeding grounds. Our results show that planning for multiple species across the entire year represents a far more efficient approach to land use planning,” said Scott Wilson, Environment and Climate Change Canada research scientist and co-author on the paper.

“This study illustrates how globally crowd-sourced data can facilitate strategic planning to achieve the best return on conservation investments. No other data source could have achieved anything close to this level of detail and efficiency in spatial planning over such a vast area,” said Cornell Lab senior conservation science director and co-author Amanda Rodewald.

“Prioritizing sites in which to invest our conservation dollars will dramatically improve our returns on the roughly $1 billion spent annually on the conservation of birds by government and nonprofit organizations, often in the absence of spatially explicit information on year-round abundance or geographical representation,” said Peter Arcese, co-author and FRBC Chair in Applied Conservation Biology at University of British Columbia.

American blackpoll warblers, their long migration


This April 2015 video from the USA says about itself:

Amazing Migration: Blackpoll Warbler

New technology is allowing researchers to track the incredible 1,700-mile non-stop migration of Blackpoll Warblers over the Atlantic Ocean from their home in the Adirondacks and Eastern Canada to South America.

From the University of Guelph in Canada:

Tiny song bird makes record migration

March 19, 2019

Summary: The bird’s trek between its breeding grounds in the central and western boreal forest of North America and its winter home in the Amazon Basin is one of the longest songbird migrations recorded. Describing a route arcing across North America and including a transoceanic flight to South America, the study confirms an epic migration journey that scientists had long suspected but not yet proved. Tracking their route is key to solving the birds’ decline.

It’s an epic journey for a tiny bird.

For the first time, University of Guelph biologists have tracked an annual migration of up to 20,000 kilometres made by the 12-gram blackpoll warbler, one of the fastest declining songbirds in North America.

The bird’s trek between its breeding grounds in the central and western boreal forest of North America and its winter home in the Amazon Basin — one of the longest songbird migrations recorded — is the topic of a new paper by a research team headed by U of G biologist Ryan Norris.

The paper was published today in the journal Ecology.

Describing a “great circle route” arcing across North America and including a transoceanic flight to South America, the study confirms an epic migration journey that scientists had long suspected but not yet proved.

In 2015, Norris and other biologists were the first to show that blackpolls breeding in the Maritimes and New England complete a non-stop transoceanic flight of up to three days and about 2,700 km along the eastern coast of the United States.

For this new study, they looked at the full migration of birds from central and western breeding populations.

“It’s amazing,” said Norris, who worked on the study with Hilary Cooke, associate conservation scientist with Wildlife Conservation Society Canada. “A bird weighing a couple of loonies travels from the western edge of North America all the way to the Amazon basin — and, in between, traverses the Atlantic Ocean.”

Other co-authors were integrative biology professor Amy Newman and U of G grad students Bradley Woodworth, Nikole Freeman and Alex Sutton, as well as researchers from other universities, conservation groups and national parks in Canada, the U.S. and Australia.

For the study, researchers tracked birds outfitted with tiny geolocators from four boreal forest sites across northern Canada and Alaska.

Total southward migration took about 60 days on average over distances ranging from 6,900 km for birds breeding in Churchill, Manitoba, to 10,700 km for populations on the western edge of the continent in Nome, Alaska.

Blackpolls from Nome took 18 days to fly across North America to the Atlantic coast of the Carolinas. There, the birds spent almost a month fattening up to double their body weight before a non-stop, 2 ½-day flight across open water to overwintering grounds in northern Colombia, Venezuela and Brazil.

They covered between 2,250 and 3,400 km for that transoceanic hop.

Norris said scientists had long believed that blackpolls followed the great circle route. Few of the birds have ever been found in the central or western States during fall migration.

He said population numbers have fallen in recent years, perhaps caused by habitat loss and declines in insect prey related to climate change.

“To understand what’s causing the decline, we need to know their full annual cycle,” he said.

In their paper, the researchers say climate change may make extreme coastal weather events more frequent and more extreme, with unknown impacts on long-distance migratory birds.

“As a conservation scientist, what strikes me most is that in a single year a blackpoll warbler has to navigate 20,000 kilometres across land and ocean, facing risks of cat predation, storms and collisions with buildings and vehicles, all while trying to find islands of habitat to rest and refuel in our human-dominated landscapes,”said Cooke. “In comparison, the boreal region of northern Canada provides safe and high-quality breeding habitat for this declining species. Protecting Canada’s boreal forest is critical to saving this amazing songbird.”

Norris is now working with biologists in Colombia looking at the overwintering portion of the warblers’ life cycle. He said learning whether populations from across the boreal forest overwinter separately or together in South American rainforests may help improve habitat management along the migration route.

Sturgeon in trouble, video


This 20 February 2019 video from North America says about itself:

This Ancient Fish is Facing a Plummeting Population Crisis

Despite producing thousands of eggs at a time, sturgeon populations are down to about 1% of their historic population levels. Scientists are scrambling for answers.