tiz-aves:tiz-aves:[Species] | Northern gannet Northern gannets (Morus bassanus) are large seabirds o

tiz-aves:tiz-aves:[Species] | Northern gannet Northern gannets (Morus bassanus) are large seabirds occurring across the coasts of both the Atlantic and Arctic ocean. They’re not only notable for being the largest member of their family, the Sulidae, but also the depths they can reach when plunge diving, which would be around 22 metres. While originally northern gannets had been considered geese, and were placed in Anser, they since have been moved to the Morus genus, the name of which comes from Ancient Greek and translates into foolish. The reason for this name supposedly is in reference to the lack of fear breeding gannets and boobies show when threatened, sometimes getting them killed. Although males and females certainly appear similar, there are some slight differences in size and weight. On average, males, which reach a mean length of around a metre, tend to be a few centimetres larger, whereas females, which reach a mean weight of around 3.1 kilograms, tend to be 100 - 200 grams heavier.As previously hinted at, the main feeding strategy that northern gannets employ is plunge diving. I talked more in depth about the feeding strategy here, but overall the principle is really simple: fly really high, (in the case of northern gannets up to 30 metres), dive beak first into the water, and catch prey, either by taking something near the surface, or, like northern gannets sometimes do, by further swimming underwater. Here also notable is that northern gannets occasionally turn kleptoparasitic, and steal prey from other birds.Most of their diet is compromises by fish, especially those that live in dense schools, such as herrings, sand lances, cods, pollacks and menhadens. On occasion northern gannets will also feed on squids, and if they have the chance to do so, they might also scavenge for scrap and offal around fishing boats.With an average life expectancy of around 35 years, it doesn’t come as a surprise that northern gannets don’t tend to mate before having reaching an age of around 5 to 6 years, which is already older than many birds ever can reach. Breeding is done in tightly packed colonies and a pair may mate for life. They lay one pale blue, to sometimes white egg, which becomes stained over time. Both males and females partake incubation, a process that takes around 42 to 46 days. Both parents are also responsible for feeding their young, which fledge after around 84 and 97 days.The nest, which is mostly built by the male of a pair, is a pile of grass, seaweed, dirt and feathers, that is held together by excrement. A pair may use the same nest for years, gradually building it up to a tall mount. Northern gannets are significantly less picky than other birds, when it comes to nest building materials, which is why researchers have found them using stuff such as a plastic frog, shotgun-shell casings, false teeth, a gold watch and many more. Once the breeding season ends, adult gannets disperse over a wide area, travelling up to 1.600 kilometres, which is still a hundred kilometres longer than the distance from Berlin to Barcelona. Though some individuals go even further one travelling around 2700 kilometres from Alderney to Scandinavian waters.Adult northern gannets face relatively little natural predation, most of the danger coming from only two eagle species. Eggs and nestlings on the other hand rely on their parents to be protected from things such as great black-backed gulls, American herring gulls, common ravens, Eurasian ermines, and red foxes. Due to the taking of eggs and slaughtering of adults, a practice barely continued today, the northern gannet greatly declined in the 19th century. Over the course of many decades, they were put under protection in most of their range, which allowed them to gradually re-establish themselves, their populations still growing annually by 3 - 5% to this day. As a result, the IUCN assesses this species to be of least concern.Photo credits: Maryse Neukomm, Christoph Moning, Blair Dudeck [1], [2]Sources: Wikipedia the Free Encyclopaedia, The Cornell Lab of Ornithology, Audubon Society, Ocean ExpidtionsBuy me a tea (unless your name is Alex, in which case you need to keep your spending in check and I owe you lots of bird posts I am so sorry)Written the 25th and published the 29th of November, 2021 I know they are generally considered goofy birds, but I find them to look very elegant, even a little spooky under the water! Also if you look closely you might even see some attempted kleptoparasitism in the video! -- source link

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