GearGuide: Camera Lenses for Bird Photography | Nature and Travel Photo Specialists

GearGuide: Camera Lenses for Bird Photography | Nature and Travel Photo Specialists

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Global warming has reversed 2,000 years of cooling in the Arctic

The Arctic is at it warmest for 2,000 years despite the fact natural cycles mean the area should be cooling, according to research which scientists say proves climate change is man-made.

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Birds to sense the lengthening days of springtime

A photochemical in the brain allows birds to sense the lengthening days of springtime and thus know when to breed, reveals research part-funded by the Wellcome Trust. Scientists at the University of Oxford and colleagues have identified a gene in the chicken genome that produces a light-sensitive molecule in the hypothalamus region of a bird’s brain. The molecule acts as a light receptor deep in the brains of birds, detecting changes in day length and triggering the seasonal development of the reproductive system.

“When you hear birds singing in the springtime, it’s a light-sensitive molecule deep in their brain that’s triggered this reproductive event,” said Professor Russell Foster from the University of Oxford, who led the study. “By timing their mating to the changing seasons, birds can make sure that there will be enough food around for their chicks.”

Previous research has shown that birds do not use their eyes to measure the increasing number of hours of sunlight, but instead rely on an area deep in the brain. This is possible because bird skulls and brain tissue let a lot of light through. The molecule identified belongs to a family of photopigments known as the VA opsins, which are not involved in vision but detect slow changes in the light environment such as dawn and dusk. The researchers showed that when the gene for the pigment is active in nerve cells, the cells generate electric signals in response to light. They also demonstrated that chicken VA opsin is present in the hypothalamus.

“This evidence is as strong as we can get that we’ve pinpointed the light receptors that tune birds’ responses to the changing seasons.” said Dr Stephanie Halford, first author on the study. “We have shown that chickens have a pigment called VA opsin, that it reacts to light, and that it is around in exactly the part of the bird’s brain that we know responds to day length.”

The research team has also found VA opsins in amphibians, reptiles and other birds, and believe that this deep-brain mechanism may be found in a range of species across all vertebrates apart from mammals.

Image: © Peter Brooks

Reference

Halford S et al. VA opsin-based photoreceptors in the hypothalamus of birds. Curr Biol 2009.

Human activity is driving Earth's 'sixth great extinction event'

Population growth, pollution and invasive species are having a disastrous effect on species in the Southern hemisphere, a major review by conservationists warns.

Earth is experiencing its "sixth great extinction event" with disease and human activity taking a devastating toll on vulnerable species, according to a major review by conservationists.

Read the full story in Mail & Guardian

Save 50/50

50/50 has been one of the most successful SABC programs and been running for +- 25 years
Its the only local program that speaks out about environmental and animal abuse.
South Africa has been identified by the United Nations as one of the counties to be worst hit by global warming.
It is imperative that our national broadcaster not only retain 50/50 but does more to heighten awareness on these crucial issues.

50/50 has good advertising support and the pulling of the program has bewildered the producers, who then offered to find their own sponsors, and have been declined. It seems they want 50/50 gone at all costs!

It has been surmised that 50/50 has stepped on too many abusers toes who are pressurising our cripple national broadcaster!

If you care, sign up at the following link and also please circulate this link as quickly and broadly as possible http://www.save5050.co.za/

Birdlife SA's new website

The revamped Birdlife website sponsored by The Diamond Route is up and running. Looks good!

Photographers Beware!

"A word of warning: I was slightly handicapped this year in the lens department because the baggage handlers at Johannesburg International Airport ripped apart a locked Pelican case containing by trusty 300mm 2.8 lens. It serves as a reminder not to check in anything of valuable into flights going through SAA handling."

As this is the third incident like this that I heard about in the last month, it looks like the O.R Tambo baggage handlers have learn't to be selective and look for high value items that have been checked. Two of the three were visiting overseas photographers. Not good for our image as 2010 approaches.

Digging for Mining Licences - M&G

Coal-mining companies with black empowerment partners who have friends in high places are posing a growing threat to some of South Africa's most sensitive environmental areas.

The companies are seeking to cash in on South Africa's coal resources, mainly in Mpumalanga, by supplying cheap coal to Eskom.

o The empowerment partners of Coal of Africa, which is prospecting near heritage and national park site Mapungubwe, include new Minister of Human Settlements Tokyo Sexwale's Mvelaphanda group.


o The sister of the former trade minister Mandisi Mpahlwa, (who is President Jacob Zuma's financial adviser) Mandlakazi Mandaka, is the BEE partner of Delta Mining Company, which has been handed a permit to prospect in Wakkerstroom. Concerns have been voiced about the impact of mining on the area's important wetlands.


o In Dullstroom ANC funding vehicle Chancellor House has applied for a prospecting licence amid allegations that it is riding roughshod over local stakeholders.


o In Belfast farmers have mounted a court challenge to Exxaro, Africa's largest black-controlled diversified mining company and the biggest supplier of coal to Eskom.

Read more in Mail & Guardian

Making Sure The Leopard Has A Future

The leopard is one of Africa’s most charismatic members of the cat family. Its beauty and elusive nature, combined with its profile as one of South Africa’s “Big Five”, have made it a favourite with tourists and hunters alike. The animal therefore has huge economic value due to its popularity within the tourist and hunting industries, as well as being an ecologically important predator at the top of the food chain in many ecosystems. The presence of leopards in an area is an indication of a healthy, well-functioning ecosystem. On the other hand, leopards are maligned by farmers whose livestock are slain with devastating economic repercussion. Understanding the intricate ecological and economic processes affecting the existence of leopards in South Africa will be fundamental to ensuring its future existence. Read more about Leopard Conservation in South Africa.