White-tailed eagle and osprey fighting a majestic battle over desirable Nauvo property

Struggle commenced with osprey's return from winter migration

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The two most noble birds of prey in the Finnish archipelago, the white-tailed eagle (Haliaeetus albicilla) and the osprey (Pandion haliaetus) are fighting a heated battle for a ”Net-nest” that originally belonged to the osprey.
      Battle commenced on Sunday when one of the former-owner ospreys returned from its winter migration and discovered that its home in Nauvo in the Archipelago Sea had been taken over by a pair of white-tailed eagles during the winter.
     
The contest is a repeat of last year's, when victory went to the appreciably smaller osprey.
      A camera set up next to the osprey's nest by the Turku University of Applied Sciences recorded the return of the osprey to the nest early on Sunday morning.
      So far, only one osprey has arrived in the nest - a female one, according to Sami Lyytinen, a member of WWF Finland’s white-tailed sea eagle working group, which has saved the white-tailed sea eagle from the verge of extinction.
      It is difficult to distinguish the gender on the basis of the webcam but ”the osprey has been scraping the bottom of the nest, with all the dust and dirt flying around it. On the other hand, male birds can do that, too”, Lyytinen reported.
      The white-tailed eagle and the osprey have taken turns to appear at the nest every 30 seconds, but not once has the camera captured them there simultaneously.
      ”In practice, the white-tailed eagles have regarded the nest as their own, but now they are beginning to lose interest as no eggs have appeared and they have nothing to defend”, Lyytinen notes.
     
”The osprey has more to win, and it wants to be the king. More scuffles are to be expected”, Lyytinen predicts.
      Last year, a similar situation prevailed at the same nest. The osprey even laid an egg, but its nesting failed. The white-tailed eagles were then young and it is thought possible that last year's residence was more of a drill on their part. At least they gave up occupancy in favour of the smaller bird.
      ”Last year we had one image in which an osprey darted towards the white-tailed eagles. Similar incidents have certainly happened even this time, they just have not been captured by the camera yet”, Lyytinen assumes.
     
Lyytinen regards it as more likely that the osprey is the one to eventually occupy the nest. With spring arriving so rapidly, the white-tailed eagle is no longer likely to start breeding in the nest. However, further altercations over the occupation of the nest are likely, while there is also a risk that the osprey’s nesting could fail because of fighting.
      Last year, a camera set up next to another osprey's nest recorded an attack by a white-tailed eagle against one of the osprey young in the nest on the northern island of Hailuoto. The young osprey did not survive the attack.
      According to Lyytinen, a white-tailed eagle is able to kill even an adult osprey. One such incident has been recorded in Finland.
      ”However, an osprey is no soft touch for a white-tailed eagle. Even though the osprey is a good deal smaller than than the other bird, it knows very well how to defend itself. Both of them want to survive, which is why they are not likely to start a real turf war intentionally”, Lyytinen notes.
      Ospreys are suffering from a severe shortage of nest sites, and in the spring, nests do not have name tags or "reserved" signs attached to them.
     
The one who occupies a nest first has the upper hand, Lyytinen says. However, there was an incident last year when a determined osprey managed to chase a hatching white-tailed eagle out of the nest.
      There are more than 350 nesting pairs of white-tailed eagles in Finland, and 1,200 pairs of ospreys. The population of ospreys has been on a slight upward trend, while the population of white-tailed eagles has been increasing strongly.
     
The current situation at the nest site appears stable. On Wednesday the camera has captured only the osprey in the nest at irregular intervals, while no sighting of the white-tailed eagle has been recorded.
      The nesting of the white-tailed sea-eagles (or the osprey(s) - may the best bird win) can be observed on a webcam on the address given below. The image refreshes automatically every ten seconds.
      The drama has already got people gripped, and the number of visitors to the webcam site has increased dramatically.


Previously in HS International Edition:
  White-tailed eagle pair expecting offspring (6.4.2009)
  Hopes that white-tailed eagle pair´s nesting can be caught on camera (11.2.2009)
  Northern webcam records white-tailed eagle attacking osprey nest (5.8.2008)

Links:
  Osprey (Wikipedia)
  White-Tailed Eagle (Wikipedia)
  Osprey webcam, Nauvo (click on the image)
  WWF Finland

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