Hoot, Hoot?
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Snowy owls are heading south throughout the Northeast, including this one photographed on Dec. 3 at Presque Isle State Park's Gull Point near Erie, Pa. (AP Photo, Erie Times-News | CHRISTOPHER MILLETTE)
Snowy Owls are not usually seen on beaches with sand an pebbles.
Are they the new Goose?
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December 09, 2013 at 5:00 AM, updated December 09, 2013 at 5:08 AM
...What's happening is called an irruption, (click here) meaning a large migration of a species moves temporarily into areas where they're not normally found. When it comes to snowy owls, there's no way to positively predict when this is going to happen, although there are a lot of theories as to what causes it.
There's a long accepted belief that snowy owls move south in winters when the lemming population in the high Arctic is low. But not everyone agrees with that. Others postulate that these owls move south in big numbers even when lemming numbers are good because an abnormally high number of young have survived and they and other predators are competing for winter food. And still other ornithologists think weather has something to do with a mass movement even though these owls live and breed on a treeless tundra as far north as you can go.
Snowy owls are currently being found in every northeastern state and even in some southern ones. Six of them have been sighted at the Syracuse, N.Y., airport alone. In New Jersey, they're scattered up and down the coast, and no doubt there are some unseen inland. The most astounding statistic I've seen so far came from the island of Newfoundland, where 138 were found in one day....
The real questions is want happened to the lemming and vole populations in the Arctic and is the Snowy Owl becoming Threatened or Endangered in the normal range?
...A snowy owl's preferred meal is lemmings (click here) —many lemmings. An adult may eat more than 1,600 lemmings a year, or three to five every day. The birds supplement their diet with rabbits, rodents, birds, and fish.
These magnificent owls sometimes remain year-round in their northern breeding grounds, but they are frequent migrants to Canada, the northern United States, Europe, and Asia. Lemming availability may determine the extent of southern migration, when owls take up summer residence on open fields, marshes, and beaches....
This is a 2012 report which states Lemming populations may be crashing with maximum numbers changing to every 8 years than every 5 years.
...In some regions, (click here) however, the cyclic pattern is changing, especially the cycle duration. On Wrangel Island, northeast Russia, the period between years with peak densities has increased from five years in the 1970s to close to eight years in the 1990s and 2000s...
The third graph shows a consistent decrease in the Snowy Owls preferred diet, namely the lemmings. Snowy Owls are raptors. They hunt like Eagles do.
The reason for the decrease in lemming population needs to be investigated. And the Snowy Owl population now in their very southern range has to be discerned to know if birds usually seen in their southern range are not the ONLY owls left. It could be that a large population with ever increasing numbers of Snowy Owls now in their southern range may be crashing with their food source.
Surprise, surprise; it is climate. The QUALITY of the SNOW TEMPERATURE determines population. Warmer snows result in predator success while cold snows results in Lemming success.
This is a 2012 report which states Lemming populations may be crashing with maximum numbers changing to every 8 years than every 5 years.
...In some regions, (click here) however, the cyclic pattern is changing, especially the cycle duration. On Wrangel Island, northeast Russia, the period between years with peak densities has increased from five years in the 1970s to close to eight years in the 1990s and 2000s...The third graph shows a consistent decrease in the Snowy Owls preferred diet, namely the lemmings. Snowy Owls are raptors. They hunt like Eagles do.
The reason for the decrease in lemming population needs to be investigated. And the Snowy Owl population now in their very southern range has to be discerned to know if birds usually seen in their southern range are not the ONLY owls left. It could be that a large population with ever increasing numbers of Snowy Owls now in their southern range may be crashing with their food source.
Surprise, surprise; it is climate. The QUALITY of the SNOW TEMPERATURE determines population. Warmer snows result in predator success while cold snows results in Lemming success....Wet snow helps predators (click here)
Nils: When they crash, they crash to very low densities and they crash most likely because of the predator population building up. So they crash to very low levels and it takes time for them to build up. And to build up very high densities, they need a period in which they are free from heavy predation and that's what they get during the snow, during the winter period, and it takes three to four years to build up such a population.
But in the mid ‘90s, all this was gone and what we found in this paper published in Naturewas that the snow had changed from being soft and dry to being wet. Hence, the lemmings could not build up....
The Snowy Owl has very few predators, arctic foxes, corvids and swift-flying jaegers; as well as dogs, gray wolves and avian predators. While these predators do have an effect on the number of Snowy Owl in the arctic, it doesn't mean they are very successful. Snowy Owls will protect their nests from predators and they are very successful in doing so.
As a keystone species it controls the populations of other animals in the ecosystem.
It is a keystone species. It is a predator. A keystone species is like a keystone in the center of an arch. The arch collapses without the center stone.
Unfortunately, this movement of the owls and the deteriorating ecosystem that supports the Lemmings is a very big deal. Very big.
The Snowy Owl has very few predators, arctic foxes, corvids and swift-flying jaegers; as well as dogs, gray wolves and avian predators. While these predators do have an effect on the number of Snowy Owl in the arctic, it doesn't mean they are very successful. Snowy Owls will protect their nests from predators and they are very successful in doing so.
As a keystone species it controls the populations of other animals in the ecosystem.
It is a keystone species. It is a predator. A keystone species is like a keystone in the center of an arch. The arch collapses without the center stone.
Unfortunately, this movement of the owls and the deteriorating ecosystem that supports the Lemmings is a very big deal. Very big.
