Petrel causes a storm for New Zealand

New Zealand Storm-petrel Oceanites maorianus was presumed extinct until its rediscovery by bird watchers in New Zealand’s Hauraki Gulf Marine Park in 2003.  Since then there has been much speculation as to whether this diminutive 35 g seabird breeds on one of the area’s many Islands, or is a visitor to New Zealand waters, breeding elsewhere, and has thus little claim to the name ‘New Zealand’ Storm-petrel.

With funding from The Birdlife International Community Conservation Fund – and support of the Hauraki Gulf Forum, DOC, the Auckland Council and Forest & Bird (BirdLife in New Zealand) – a team of researchers have now collected the best evidence yet that the Critically Endangered bird breeds somewhere in the Hauraki Gulf Marine Park.

Before dawn on Wednesday 1 Feb, Chris Gaskin, Dr Matt Rayner (University of Auckland), Shane McInnes (DOC) and boat skipper Brett Rathe headed out into the Hauraki Gulf to try and capture New Zealand Storm-petrels and  identify signs of breeding on the birds.

The team was able to capture five birds using specially designed net guns.  Most importantly, four of the birds showed signs of breeding with bare ‘brood patches’ on their belly that are  used to incubate eggs. This evidence strongly suggests the birds are breeding locally, with islands within the Hauraki Gulf Marine Park most likely sites.

“It’s wonderful to think that these birds are breeding right now on islands within the Hauraki Gulf, quite possibly in sight of where we captured them”, said Chris Gaskin.

The team will continue their capture programme through February and March to find out as much as they can about the birds’ breeding cycle. Armed with that information they will determine when would be the best time to try and track birds to their island breeding location using radio tracking devices.

Read on:  http://www.birdlife.org/community/2012/02/petrel-causes-a-storm-for-new-zealand/

Tiny Crooners: Male House Mice Sing Songs to Impress the Girls

ScienceDaily (Jan. 26, 2012) — It comes as a surprise to many that male house mice produce melodious songs to attract mates.  Unfortunately for us, because the melodies are in the ultra-sonic range human ears cannot detect them.  Through spectrographic analyses of the vocalizations of wild house mice, researchers at the University of Veterinary Medicine, Vienna  have found that the songs of male mice contain signals of individuality and kinship. 

Their results appear in the journal Physiology & Behavior and in theJournal of Ethology.

It has been known for some time that house mice (Mus musculus) produce ultrasonic vocalizations (USVs) during courtship but it has generally been assumed that these are no more than squeaks. However, recent spectrographic analyses have revealed that USVs are complex and show features of song.  Although the vocalizations are inaudible to human ears, when playbacks of recorded songs are slowed down their similarity to bird song becomes striking.  Frauke Hoffmann, Kerstin Musolf and Dustin Penn of the University of Veterinary Medicine, Vienna’s  Konrad Lorenz Institute of Ethology aimed to learn what type of information is contained in males’ songs for the discerning ear of the female mouse to detect.  Their initial studies, the first to study song in wild mice, confirmed that males emit songs when they encounter a females’ scent and that females are attracted to males’ songs.  Additionally, the scientists discovered that females are able to distinguish siblings from unrelated males by their songs – even though they had previously never heard their brothers sing.

In their recent studies, Penn’s group recorded and analysed the courtship calls of wild-caught male house mice for the first time, using digital audio software to examine parameters such as duration, pitch and frequency.  They found that males’ songs contain “signatures” or “fingerprints” that differ from one individual to another.  Moreover, they confirmed that the songs of siblings are very similar to one another compared to the songs of unrelated males, which helps explains how females can distinguish unrelated males.  This finding could potentially lead us to understand how female mice avoid inbreeding. 

Interestingly, in some species of birds the males with the most complex songs appear to be most successful at attracting females.  Further studies are needed to determine whether the complexity of male mouse vocalizations has an effect on females that is similar to that of “sexy syllables” in birds.

The vocalizations of wild house mice differ significantly from those of inbred strains of laboratory mice.  Wild male mice produce more syllables within high frequency ranges than laboratory mice, a result that is consistent with other studies that find genetic effects on mouse song. “It seems as though house mice might provide a new model organism for the study of song in animals,” says Dustin Penn.  “Who would have thought that?”

http://www.sciencedaily.com/releases/2012/01/120126100633.htm

Seals use incredible navigation skills to return to site where they were born

Forget Satnav, now there is seal-nav. Scientists have discovered that some seals are capable of finding their way back to the exact spot where they were born even after spending five years out at sea.

The Antarctic fur seals' remarkable homing instinct, which is thought to be the most accurate of any sea mammal, allows the creatures to return to within a single body length of the spot where they were born to give birth to their own pups.

Nearly four million of the sea mammals breed in huge colonies on the virtually featureless beaches of South Georgia every year. After being born, the seals spend five years out at sea feeding before returning to the island to breed.

Using radio tags placed on 335 seals shortly after they were born, researchers at the British Antarctic Survey have discovered that each seal returns to exactly the same location on the beach once they start breeding year after year.

But while typical human Global Positioning Systems (GPS), which use satellites orbiting the earth, can pinpoint a location to an accuracy of around 15 feet, the seals were found to be accurate down to as little as six feet.

Exactly how the seals achieve this feat has left the scientists baffled, but they believe the creatures use a kind of internal compass that helps them find their way across the Southern Ocean to the correct location on the right beach.

Read more here ...

Antarctic fur seals breed where they were born

Scientists have discovered that female Antarctic fur seals have an uncanny ability to return to within a body length of where they were born when it's time to breed.

Even if they don't manage to get this close, the majority of females give birth to pups within 12 metres of where they themselves were born.
'It's as if they have some sort of in-built GPS system,' says Dr Joe Hoffman from the University of Bielefeld in Germany, who led the study. 'Or it could be simply that they're using cues, like smell, that we can't measure. What is remarkable is that the colony is featureless, so it's impressive they find their way back.'
What's also striking is that these seals may have spent up to five years feeding hundreds of kilometres out at sea before coming home.
Knowing more about how these seals live their lives will help scientists understand how populations affect the fragile local ecosystem of South Georgia in the south Atlantic Ocean.

Read on ...

Mercury 'turns' wetland birds such as ibises homosexual

Mercury affects the behaviour of white ibises by "turning them homosexual", with higher doses resulting in males being more likely to pair with males.


Scientists in Florida and Sri Lanka studied the effect of mercury in the birds' diet. Their aim was to find out why it reduced the ibises' breeding.

Mercury pollution can come from burning coal and waste, and run-off from mines.

The report, in Proceedings of the Royal Society B, shows that wetland birds are particularly badly affected by it.

Although the researchers already knew that eating mercury-contaminated food could affect an animal's development, they were surprised by the "strange" results of this experiment.

"We knew mercury could depress their testosterone (male sex hormone) levels," explained Dr Peter Frederick from the University of Florida, who led the study. "But we didn't expect this."

The team fed white ibises on food pellets that contained concentrations of mercury equivalent to those measured in the shrimp and crayfish that make up the birds' wetland diet.

The higher the dose of mercury in their food pellets, the more likely a male bird was to pair with another male.

Dr Frederick and his colleagues say the study shows that mercury could dramatically reduce the breeding rates of birds and possibly of other wildlife.

The exact mechanism that causes this change in behaviour is not yet fully understood.

But mercury is known to disrupt hormonal signalling, so it could have a direct impact on the sexual behaviour that is mediated by those hormones.

Importantly, the males with the higher mercury doses performed far fewer courtship displays, so they were more likely to be "ignored" by females.

Chemical mimic
Wetland habitats, like the Florida Everglades that are home to these birds, are particularly vulnerable to mercury contamination.

Bacteria that live in the thick, oxygen-free sludge chemically alter the mercury, turning it into its most toxic form - methylated mercury.


And this chemical can act as a sort of biological impostor, mimicking hormones that act as the body's natural chemical signals.

Some of these signals are involved in reproductive behaviour - they may stimulate an animal to carry out a courtship display or motivate it to mate.

"We're seeing very large reproductive effects at very low concentrations [of mercury]," said Dr Frederick. "So we really need to be paying more attention to this."

'Goldilocks mixture'
When a wetland is warm all year round, like the Everglades, it is an ideal environment for this methylation process.

Scientists refer to these conditions as a "Goldilocks mixture".

Dr Frederick says that measures could be taken to clean up any sources of mercury where they are close to wetland habitats - for example by filtering or "scrubbing" the smoke from nearby coal-burning power plants.

Gary Heinz, a wildlife researcher from the US Geological Survey in Maryland, who was not involved in the study, told the BBC that mercury was "a serious problem in many aquatic environments".

"It cannot be broken down, only be moved about and transformed from one chemical form to another," he said.

"And any effect that might reduce the productivity of a species would likely be harmful in nature."

Dr Heinz said the next step would be to study the reproductive behaviour of mercury-contaminated animals in the wild.

By Victoria Gill

Science and nature reporter, BBC News

Mercury 'turns' wetland birds such as ibises homosexual

Mercury affects the behaviour of white ibises by "turning them homosexual", with higher doses resulting in males being more likely to pair with males.


Scientists in Florida and Sri Lanka studied the effect of mercury in the birds' diet. Their aim was to find out why it reduced the ibises' breeding.

Mercury pollution can come from burning coal and waste, and run-off from mines.

The report, in Proceedings of the Royal Society B, shows that wetland birds are particularly badly affected by it.

Although the researchers already knew that eating mercury-contaminated food could affect an animal's development, they were surprised by the "strange" results of this experiment.

"We knew mercury could depress their testosterone (male sex hormone) levels," explained Dr Peter Frederick from the University of Florida, who led the study. "But we didn't expect this."

The team fed white ibises on food pellets that contained concentrations of mercury equivalent to those measured in the shrimp and crayfish that make up the birds' wetland diet.

The higher the dose of mercury in their food pellets, the more likely a male bird was to pair with another male.

Dr Frederick and his colleagues say the study shows that mercury could dramatically reduce the breeding rates of birds and possibly of other wildlife.

The exact mechanism that causes this change in behaviour is not yet fully understood.

But mercury is known to disrupt hormonal signalling, so it could have a direct impact on the sexual behaviour that is mediated by those hormones.

Importantly, the males with the higher mercury doses performed far fewer courtship displays, so they were more likely to be "ignored" by females.

Chemical mimic
Wetland habitats, like the Florida Everglades that are home to these birds, are particularly vulnerable to mercury contamination.

Bacteria that live in the thick, oxygen-free sludge chemically alter the mercury, turning it into its most toxic form - methylated mercury.


And this chemical can act as a sort of biological impostor, mimicking hormones that act as the body's natural chemical signals.

Some of these signals are involved in reproductive behaviour - they may stimulate an animal to carry out a courtship display or motivate it to mate.

"We're seeing very large reproductive effects at very low concentrations [of mercury]," said Dr Frederick. "So we really need to be paying more attention to this."

'Goldilocks mixture'
When a wetland is warm all year round, like the Everglades, it is an ideal environment for this methylation process.

Scientists refer to these conditions as a "Goldilocks mixture".

Dr Frederick says that measures could be taken to clean up any sources of mercury where they are close to wetland habitats - for example by filtering or "scrubbing" the smoke from nearby coal-burning power plants.

Gary Heinz, a wildlife researcher from the US Geological Survey in Maryland, who was not involved in the study, told the BBC that mercury was "a serious problem in many aquatic environments".

"It cannot be broken down, only be moved about and transformed from one chemical form to another," he said.

"And any effect that might reduce the productivity of a species would likely be harmful in nature."

Dr Heinz said the next step would be to study the reproductive behaviour of mercury-contaminated animals in the wild.

By Victoria Gill

Science and nature reporter, BBC News