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.

Early frogspawn in Cornwall already


This video from England is called Common Frogs in the Garden.

From daily The Guardian in Britain:

Frogs breeding in November due to mild weather

Frogspawn spotted in Cornwall, months before the usual spring spawning time, is earliest sighting in almost a decade

Mild autumn weather has led to frogs breeding five months early, with frogspawn sighted in Cornwall this week. It is the earliest frogspawn recorded in nearly a decade.

The Woodland Trust was alerted to the frogspawn by a National Trust ranger, who had spotted the common frog’s spawn at the North Predannack Downs nature reserve on the Lizard Peninsula.

“This year I first saw frog spawn on 21 November, which is early, but not unheard of in a Cornish context,” said Rachel Holder, the ranger who first spotted the frogspawn. “The gamble of getting ahead in the breeding game must be worth taking, and the risk of a severe cold snap which could freeze the spawn is worth braving,” she said.

Frogspawn [is] usually seen in March across the UK, with the earliest occurrence in recent history being on 26 October, in 2005.

Dr Kate Lewthwaite, project manager for Woodland Trust’s Nature’s Calendar , said: “Although spring is generally arriving earlier, to receive a frogspawn sighting before winter has properly begun is highly unusual.

“Given the reasonably mild weather we have been enjoying recently, it is possible for frogs to be fooled into spawning early, but sadly it is unlikely the spawn will now survive the frosts we are experiencing,” she said.

November has been mild and very wet so far, according to the Met Office, with average temperatures nearly 2C above the long-term average, and 93.1mm of rainfall.

Frogspawn, which has the appearance of a thick translucent jelly with dark specks, often contains 5,000 eggs and is laid at one time. Tadpoles begin to emerge after a month, although early spawn is vulnerable to freezing during the winter months while it floats on the top of the pond. As frogs mate once per season, their breeding effort for the year may be wasted if spawn is laid when the conditions are not right.

Chris Hickman, from the Woodland Trust, told the Guardian that the early UK sightings of frogspawn, “highlights the wider issue that frogs are looking at spawning early, or having to adapt, because climate change is changing the natural environment in England.”

He added, “it’s not something that we’ve had for a long time and we have to establish whether this will be a one off, or maybe there are other frogspawn sightings out there that perhaps people haven’t yet reported.”

Matthew Oates, a naturalist at the National Trust, said he had noticed how climatic changes have affected the seasonal behaviour of species, such as the purple emperor caterpillar not hibernating, and this autumn he has heard the evening chorus of song-thrush and robins singing. The naturalist said that he expects hazel catkins, which traditionally appear mid-January, to bloom before Christmas.

There have been early first sightings of other species in recent years. According to the Woodland Trust, snowdrops which are traditionally out in spring have been sighted early in November and December since 2001. Ladybirds, which historically hibernate during the winter months, were spotted in December every year between 2002 and 2008 and also in 2011.

Young hammerhead sharks, new research


This video is called Shark Academy: Scalloped Hammerhead Sharks.

From Wildlife Extra:

Endangered juvenile sharks migrate into unprotected waters

The movements of a young female Hammerhead Shark have been tracked for the first time, revealing vulnerable gaps in the present protection plans.

Hammerhead Sharks are listed as threatened with the IUCN and numbers have declined by more than 90 percent in some parts of the world, particularly Scalloped Hammerhead sharks, found in the Gulf of California, Mexico.

These are susceptible to being caught by fishing nets while moving into the open sea, but little information exists on their exact movements, especially those of juvenile sharks as they go through the critical period of adolescence.

Current protection plans prohibit commercial fishing from large vessels within 50 nautical miles of the coast. However, findings from this study reveals the young sharks venture into the open seas to fish, meaning they are still vulnerable to being caught in fishing nets.

Researchers from the Centro Interdisciplinario de Ciencias Marinas, Mexico and the University of California, Davis, USA tagged three live juvenile hammerhead sharks in Mexico’s Gulf of California so they could be tracked through adolescence.

The results of one of these tags, which was downloaded after fishermen caught one of the sharks, revealed the female shark travelled 3,350 km, and helped pinpoint potential key sites needing protection.

She was found to swim within a school of fellow hammerheads at an offshore island during the day, but migrated away at night, diving to greater depths to feed on fish and squid, sometimes as deep as 270m.

This behaviour, the scientists believe, maximises her foraging opportunities and continuing growth, and partially explains the early migration of this juvenile female to off-shore waters for richer food. Scalloped Hammerhead Shark pups have high metabolic rates and as they grow older require higher ration levels to fulfil their energetic needs.

Study author Mauricio Hoyos from Pelagios Kakunjá (a Mexican NGO) said “The key to protecting this species is detecting their nursery grounds and protecting them in their more vulnerable stages. This is the first time ever that we have an idea of the behaviour of this life stage in this zone and this information will be important to design management plans to protect this species in Mexico.”

The research suggests that juvenile female hammerheads are trading off the risks of greater exposure to predators in the open sea, with better food sourcing opportunities.

However their ventures to the open sea means current management measures for sharks set by the Mexican government may not be sufficient for the conservation of this species.

This new information highlights hammerhead sharks may still be in danger, due to their use of both coastal and offshore waters during early life stages. The researchers say that coastal nursery grounds and offshore refuge areas for scalloped hammerheads are therefore critical habitats where protected marine reserves should be sited.

Study author James Ketchum from Pelagios Kakunjá (a Mexican NGO) said: “For the first time, we’ve seen the shift from a coastal-inhabiting juvenile to a migratory adolescent that remains mostly offshore in order to maximise growth and reproductive potential. Because of their dependence on both coastal and offshore waters during their early life-stages, we think that they may be more susceptible to fisheries than previously thought, and current protective measures in Mexico may unfortunately be insufficient.”

Fallow deer fight, video


This is a video of two male fallow deer fighting during the mating season.

They don’t intend to injure each other; they want to find out who is strongest.

Joke van de Poppe in the Netherlands made the video.

Great tit attacks insect hotel, video


In this video, a great tit has found out how to catch the insects hidden in the back of the insect hotel. Maybe more glue should have been used in making the insect hotel?

Melchior van Tweel made this video in his garden in the Netherlands.

Otter swimming with fish, video


This is a video about an otter swimming with a sizable fish in its mouth.

Ruud Bomert made this video in Overijssel province in the Netherlands.

Breeding ecology of the Purple Swamphen (Porphyrio porphyrio) in the wetland complex of Guerbes-Sanhadja, north-east Algeria


Originally posted on North African Birds:

Mouslim, B., Merzoug, S. E., Rassim, K., Bouslama, Z., & Houhamdi, M. (2014). Aspects of the breeding ecology of the Purple Swamphen Porphyrio porphyrio in the wetland complex of Guerbes-Sanhadja, north-east Algeria. Ostrich 85(2): 185-191.

PDF disponible maintenant sur African Journals online.

Abstract:

The Purple Swamphen Porphyrio porphyrio is a common rail that previously was little investigated in North Africa. From 2011 to 2013, its breeding ecology was studied at two natural wetlands in north-east Algeria, namely Garaet Hadj Tahar and Garaet Messaoussa. Numbers of Purple Swamphens at both localities peaked in late April and early May. Egg-laying started in early March, whereas hatching started in late March. Peak egg-laying took place in late March and early April, and peak hatching from mid-April to early May. There were significant differences in the size and weight of eggs between years and localities. The mean clutch size was 2.75…

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