Rare weatherfish discovery in the Netherlands

This video is called European weather loach, Misgurnus fossilis, “chewing sand”.

Translated from the Dutch RAVON ichthyologists:

Thursday, November 27th, 2014

The weatherfish has been found again after 20 years in the Drentsche Aa river area. A single ranger was still able to recall that this loach species occurred about 20 years ago in the catchment area of the Drentsche Aa. Since then, attempts to see the fish were always unsuccessful. On the basis of DNA testing it could be demonstrated that the species fortunately is still present in the area.

Hundreds of thousands of amphibians helped to cross

This video from Massachusetts in the USA says about itself:

Berkshire Amphibian Migration — via Berkshire Oudoors

14 March 2012

Video copyright: Berkshire Outdoors.

Join Rene Wendell, resident naturalist at The Trustees of ReservationsBartholomew’s Cobble in Sheffield, MA, as he takes a group of volunteers into a misty March (2011) night to help migrating amphibians cross a busy road. We encounter: spotted salamanders, spring peepers, wood frogs, four toe salamanders, red backed salamanders, and an American toad.

Translated from the Dutch RAVON herpetologists:

The Netherlands helps over sixteen kilometers of amphibians to cross roads

Post published by RAVON Foundation on Wednesday, November 26th, 2014

A traffic jam from Almere to Amsterdam; so long would the procession of toads, frogs and salamanders be, if all animals helped by volunteers to cross roads in the spring of 2014 would be put behind one another. The toad working groups during the months of March and April are estimated to have helped a total of more than 230,000 amphibians across the roads. These are about 50,000 more than last year but still not as many as in the boom years 2008, 2010 and 2011, when more than 300,000 amphibians were transferred.

The complete spring 2014 report is here.

Rare spectacled hare-wallaby seen in Western Australia

This video from Australia is about the rufous hare-wallaby. They are relatives of the recenttly rediscovered spectacled hare-wallaby.

From Wildlife Extra:

Rare Spectacled Hare-wallaby sighted in Western Australia

The threatened Spectacled Hare-wallaby has been sighted near Broome in Australia after nearly a decade without any recorded sightings in Kimberley region.

Although the species is widespread throughout other parts of northern Australia, the wallaby, which gets its name from its distinctive orange fur that surrounds each eye, is considered very rare in the Kimberley region and numbers here are declining.

“We need to keep a close eye on the threats to this rare and fascinating animal so we get the right information to help it survive into the future,” said Dr Alexander Watson of WWF-Australia.

“Their shelter and feeding requirements make them highly sensitive to habitat changes, so assessing their numbers is a good indicator of overall health of the local environment.”

The Spectacled hare-wallaby uses large grass tussocks for shelter from predators and the extremely hot daytime temperatures. Inappropriate fire regimes and trampling by larger animals can put the wallaby at risk of exposure.

The Spectacled hare-wallaby is well suited for life in extreme arid conditions, having adapted to extract and retain water from their food. However, their population is still at risk from modern threats such as introduced predators, grazing, frequent fires and extreme weather events like droughts.

Still golden buttons flowers on Ameland island

Golden buttons

Warden Marjan reports today from Ameland island in the Netherlands that golden buttons are still flowering.

The normal flowering time for this species is July-October. Golden buttons need a brackish environment; which they find on the Noordkeeg area of Ameland.

Golden buttons are originally from South Africa. In 1972, it was seen for the first time in the Netherlands; first in Flevoland province, later also elsewhere.

How hummingbirds hover, new research

This video from the USA says about itself:

Realistic aerodynamic simulation reveals how hummingbirds hover

21 November 2014

The most detailed aerodynamic simulation of hummingbird flight conducted to date demonstrates that it achieves its aerobatic abilities through a unique set of aerodynamic forces more closely aligned to those found in flying insects than in other birds. The simulation was produced by Vanderbilt engineers working with a biologist from the University of North Carolina at Chapel Hill.

From Wildlife Extra:

Secret behind hummingbird aerobatic feats discovered

Just how tiny hummingbird[s] can hover in front of a flower before darting to another has always puzzled scientists.

But new research shows that this ability is more closely related to those found in flying insects than to other birds.

A three-dimensional aerodynamic simulation demonstrated that the tiny birds make use of unsteady airflow mechanisms to generate invisible vortices of air that produce the lift they need to hover and flit from flower to flower.

When a bird pulls its wings forward and down, tiny vortices form over the leading and trailing edges and then merge into a single large vortex, forming a low-pressure area that provides lift. The tiny hummingbird[s] further enhance the amount of lift they produce by pitching up their wings (rotate them along the long axis) as they flap.

However, unlike most birds, hummingbirds are also able to generate lift on the upstroke by inverting their wings. As the leading edge begins moving backwards, the wing beneath it rotates around so the top of the wing becomes the bottom and bottom becomes the top. This allows the wing to form a leading edge vortex as it moves backward generating positive lift.

Although hummingbirds are much larger than flying insects and stir up the air more violently as they move, the way that they fly is more closely related to insects than it is to other birds, according to the researchers. Insects like dragonflies, houseflies and mosquitoes can also hover and dart forward and back and side to side.

The new realistic simulation (see film above) demonstrates that the tiny birds make use of unsteady airflow mechanisms, generating invisible vortices of air that produce the lift they need to hover and flit from flower to flower.

Horseshoe crabs and knots in Delaware Bay, USA

This video from the USA is called Delaware Bay Shorebird Project.

By Nigel Clark, of the British Trust for Ornithology, in Thetford, England:

Getting to the Arctic on time: Horseshoe Crabs and Knot in Delaware Bay

Arctic breeding waders are often constrained by the availability of resources at stop over sites on their northward migration to the breeding grounds. These constraints become most acute at their last stopover before they reach the breeding grounds as late arrival, or arrival in poor condition, may lead to a reduction in breeding productivity and subsequent survival.

The situation in Delaware Bay, USA is particularly difficult for migrating waders, as they depend largely on the eggs of Horseshoe Crabs that are exposed on the beach surface. These surface eggs are abundant only when there are extremely large numbers of breeding crabs. In the early 1990’s there was a dramatic increase in the Horseshoe Crab fishery which lead to a major reduction in spawning crab numbers. This resulted in a reduction in the rate of weight gain of migrating waders, particularly Knot, and coincided with a dramatic decline in the population.

Initial responses of the conservation community were to call for a permanent ban on Horseshoe Crab fishing which lead to the imposition of harvest quotas, and in some States a complete moratorium. The first signs of a recovery in the Horseshoe Crab population are beginning to appear, which has in turn lead to the call from fishing interests for increases in fishing quotas. The conservation community had been collecting extensive ecological data over a decade which proved the link between food supplies and the condition of the birds but this is not easy to explain to non-scientists. The way forward was found after many days of discussions between all parties. The result is an Adaptive Resource Management approach and gives hope for the future of the Horseshoe Crabs and Knot.