In the hostile climate of the extreme south, reproducing but above all feeding his offspring is a feat. Penguins have understood this. The most massive of these birds of the icy seas – the emperors and royal penguins – lay a single egg, each year. The others push up to two. Their cousins The Gorfous, identifiable by the egrets on each side of their heads, stopped halfway: the females lay two eggs … but let only one. The interest of such a practice? For four of the seven species, which convent the first egg as soon as it is released, scientists have decided: this is life insurance. Ponded a few days later, the second has the right to the parents’ attention only if he has happened bad luck to his predecessor. But three other species make the opposite: they sulk the first egg and invest everything in the second.
What does such behavior rhyme? Any masterpiece requires a draft, will respond to painters and cadets in need of recognition. In an article published On October 12 in the journal Plosone , a team from the University of Otago, New Zealand, tried to go further by studying the reproduction of the upscale Gorfou. For this, the biologist Lloyd Davis took up “the oldest dataset ever gathered on these isolated and poorly known birds”, the one he had collected during a long expedition to the antipodes islands in 1998.
On these uninhabited lands, lost some 800 kilometers south-east of New Zealand, lives, or rather survives, Sclateri Eudypt, the scientific name of the Huppou Gorfou. After three and a half days of navigation and a tumultuous landing, Davis and his colleagues had been able to observe, from September to November, the whole reproduction season, from the nuptial parades to the hatching of the eggs. A particularly rich material. Except that, back in Otago, Lloyd Davis had changed their life to set up the university animal cinema department. Buried, the data. But “faced with the constant reduction of the population of this species”, the biologist decided to reopen his notebooks and to publish.
a second egg 85 % bigger
First observation: None of the first 200 eggs that scientists have observed has hatched. 40 % of them have never been brooding, others are lost, in other words ride out of the rudimentary nest erected by birds. Still others are destroyed, once the second egg is laid, on average 3.5 days later. An egg significantly larger than the first: 85 % additional mass, the most important difference so far listed in the different species of Gorfous.
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