Heat, disease killing endangered New Zealand penguin

Rising heat and disease during the nesting season are posing serious threats to one of the world's rarest penguin species, New Zealand conservation officials said Monday.

Yellow-eyed penguin, also know as hoiho, nest numbers had hit rock bottom in one of the main nesting areas around the Otago region of the southeast South Island, according to the Department of Conservation (DOC).

Fewer than 190 breeding pairs have been counted on the Otago coast this season -- down from an estimated 491 breeding pairs in 2012.

Egg hatching success was about 85 percent, but avian diphtheria infection rates were up to 100 percent at some breeding sites, where diseased chicks had died on hot days as they were still under full protection of their parent's body.

"There's no obvious pattern to the outbreak of infection, but most chicks that have been infected have also been underweight," DOC ranger Mel Young said in a statement.

"We can't be sure if illness or starvation has driven the observed mortality, but the heat certainly has played a large part too."

Staff were trying to remove the oral diphtheria lesions in the chicks' mouths, which could prevent feeding and breathing, and feeding them a rehydration formula every few days.

Temperatures in excess of 16 degrees centigrade caused discomfort to adult penguins.

Unique to New Zealand, the yellow-eyed penguin is classed as endangered and its total adult population in 2000 was estimated at 6,000 to 7,000.

The species has suffered three unidentified mass mortality events that have killed large numbers of breeding adults and juvenile birds in 1990, 1996 and 2013.

It is assumed that a marine biotoxin was responsible, but post mortems and lab tests did not pinpoint the toxin involved. Endit