The week in wildlife - in pictures

Whooper swans as the sun sets on a field in Germany. Many of these migratory birds spend the winter on open fields Photograph: Patrick Pleul/EPA

An elk stands in a field in the state radiation ecology reserve in the 30 km exclusion zone around the Chernobyl nuclear reactor near the village of Novosyolki. Belarus, Ukraine and Russia will mark the 25th anniversary of the nuclear reactor explosion in Chernobyl Photograph: Vasily Fedosenko/REUTERS

Withe-handed gibbon mother Betina hangs from a tree with her her two-week-old baby at the zoo in Ramat Gan near Tel Aviv. The birth of the gibbon surprised the zoo staff, as it had been 11 years since Betina last gave birth Photograph: Jack Guez/AFP/Getty Images

The rapid spread of lionfishes along the US eastern seaboard, Gulf of Mexico, and Caribbean is the first documented case of a non-native marine fish establishing a self-sustaining population in the region, according to recent studies. Although lionfishes originally came from the Indo-West Pacific Ocean, there are now self-sustaining populations spreading along the western Atlantic coast of the US and throughout the Caribbean. Invasive lionfishes were first reported off Florida's Atlantic coast in the mid-1980s, but did not become numerous in the region until 2000 Photograph: James Morris/NOAA /USGS

A rehabilitation grey-headed flying fox returns to the wild after being released by wildlife carers at a bat colony in western Sydney, Australia. A food shortage caused by rains, flooding and cyclones has forced flying foxes who normally feed on pollens and nectars into suburban gardens. A large number of grey-headed Flying foxes, an endangered species, have needed to be rescued from city regions after being entangled in fruit tree netting used by residents in a bid to stop the starving bats from feeding in them Photograph: Rob Griffith/AP

A collared elephant who was sedated by Kenya Wildlife Services (KWS) officers attempts to stand back up in Tsavo East national park. An ambitious exercise by KWS and the Animal Fund for Animal Welfare (IFAW) saw eight elephants in Tsavo East national park collared using GPS technology that will assist in the mapping out of migratory routes and corridors in the park and its buffer zones within the larger ecosystem. Located in different parts of the park, the collared elephants will be closely monitored for 20 months, as long as they retain the collars which will enable the KWS to effectively design intervention measures for security operations and human-elephant conflict mitigation. The last collaring in Tsavo East was done in 1972 using conventional collars that required manual tracking with radio transmitters Photograph: Tony Karumba/AFP/Getty Images

A bee pollinates a flower as it collects nectar from the plant at the California central coast seaside resort community of Shell Beach, California Photograph: Mike Nelson/EPA

Laysan albatross chick and adult caught up in the debris after the tsunami hit the Midway Atoll National Wildlife Refuge Photograph: Pete Leary/USFWS

Starlings perch on power lines above farmland near Dungeness in England Photograph: Stefan Wermuth/Reuters

A bear used to attract people to pose for photographs for €2, Elbasan, Albania. NGOs have asked Albanian government to create a law for animal protection but no such legislation has been introduced Photograph: Armando Babani/EPA

A rare species of salamander called a hellbender swims in a tank at the Bronx zoo in New York. The zoo will raise 41 juvenile hellbenders to maturity and release them into the wild in order to help preserve the species. Hellbenders are native to New York State where they are listed as a species of special concern. They are threatened by pollution and habitat destruction Photograph: Julie Larsen Maher/Reuters

A large school of fish swims near the coast of Acapulco, Mexico. Local fishermen said they had never seen such large schools of fish swim so close to the coast Photograph: Bernandino Hernandez/AP

Animal education officer at Blair Drummond safari and adventure park, Eline Van De Veerdonk, finishes putting new turf in the meerkat enclosure as staff make final preparations to animal enclosures before the park opens this Saturday for the 2011 season Photograph: Andrew Milligan/PA