The week in wildlife

A pair of fledgling barn swallows are fed on a perch above the seventh hole at the Eugene, Oregon Country Club. The most widespread species of swallow in the world, barn swallows, show remarkable agility in flight as they feed on flying insects Photograph: Brian Davies/AP

Scores of new ponds have been created and dozens more restored to help protect toads and more unusual species such as the tadpole shrimp and the one-grooved diving beetle, the Environment Agency said this week Photograph: Environment Agency/PA

A trio of Kemp's ridley turtle hatchlings make their way through the surf after being released into the Gulf of Mexico at Padre Island National Seashore, Texas Photograph: Pat Sullivan/AP

A pearl-bordered fritillary butterfly. Conservation efforts have helped a rare woodland butterfly make a successful comeback in British woods, where it had become extinct Photograph: Forestry Commission/PA

A weever fish, the UK's most poisonous fish. Staff at the Blue Reef aquarium in Portsmouth, Hampshire, are putting out warnings after a weever fish was brought into their centre by a local fisherman. Although the chances of stepping on the fish were slight, the pain endured can by 'excruciating' and can cause limbs to swell up Photograph: Blue Reef Aquarium/PA

A mule deer and her fawn make their way through a burnt-out canyon at the Old West Ranch where 30 to 40 homes have been lost to a wildfire, 10 miles south-east of the Mojave Desert town of Tehachapi, California, US Photograph: Alex Gallardo/AP

Cypress trees killed by saltwater intrusion in wetlands near Houma, Louisiana, US. Environmentalists are calling on the White House to speed up the restoration of the oil-damaged Mississippi River delta by getting BP to pay $5bn for environmental damage Photograph: Patrick Semansky/AP

An endangered hairy-nosed otter walking in a forest reserve in the state of Sabah on Borneo Island. The hairy-nosed otter, one of the rarest otter species, has been spotted in Sabah's Deramakot Forest Reserve, marking its first sighting since 1997 Photograph: Sabah Wildlife Department and Sabah Forestry Department/Reuters

Fishermen empty nets of sardines on Durban's Addington beach. The east coast of South Africa is host to an annual migration of sardines which sees millions of the fish shoaling up the coast line Photograph: Rogan Ward/Reuters

Marine diatom cells (Rhizosolenia setigera), which are an important group of phytoplankton in the oceans. Much of life on Earth depends on tiny plant plankton. They are the foundation of the bountiful ocean food web, make half the world's oxygen and suck up harmful carbon dioxide. And they are declining sharply Photograph: Karl Bruun/Courtesy of Nikon Small World/AP

A Boto Cor-de-Rosa, pink river dolphin, swims in the Negro River in Novo Airao city, northern Brazil. Physiotherapist Igor Simoes created Bototerapia (pink dolphin therapy), which involves swimming with the dolphins in the belief that the ultrasonic waves they emit will help cure health problems Photograph: Ricardo Moraes/Reuters

A nine-month-old rhinoceros called Vuma, centre, rests with two others at the animal orphanage of the private rhino and lion Nature Reserve in Krugersdorp, South Africa. The animal orphanage recently welcomed Vuma, who was orphaned after poachers hacked out his mother's horn and left her dead Photograph: Stephane De Sakutin/AFP/Getty Images

Seashells coated with oil on the shore in Dalian, China, nine days after a pipeline blast leaked 1,500 tonnes of heavy crude into the sea Photograph: Greenpeace/Reuters

Seeds of tara tree at Lomas de Lachay national reserve in the desert foothills of Huaral province in Peru. The reserve features a unique mist-fed ecosystem of wild plant and animal species, whose only source of moisture is fog from the ocean Photograph: Ricardo Icaza/EPA

A three-year-old stallion foal and his mother at the Wilhelma zoo in Stuttgart, Germany, resembling a cross-breed of a donkey and zebra. He is the eleventh foal of an endangered species that only lives at the Wilhelma zoo Photograph: Wilhelma Zoo/EPA

Two bees collect pollen from a sunflower in Utrecht, Netherlands Photograph: Michael Kooren/Reuters

Sheep graze close to electricity generating wind turbines as a rainbow is seen in the background on near the German town of Husum Photograph: Johannes Eisele/AFP/Getty Images

Sunlight is reflected off water as a coot swims in the Serpentine in Hyde Park, London Photograph: Dan Kitwood/Getty Images