Cormorants are now abundant throughout the Helsinki metropolitan area. For example, there is a swarm of cormorants that have been hanging for several weeks between Lauttasaari and Keilaniemi.
There they sit again. Along the western fairway between Keilaniemi and Lauttasaari in Kuninkaanlahti, there are about 30 black figures with whitewashed islets. The distinctive pose is reminiscent of Batman: black wings are spread in a bat-like style on the sides.
Many passers-by on both the Espoo and Helsinki sides have drawn attention to the fact that hated and admired cormorants have gathered in large numbers near the shores.
“There are a surprising number of them now. In front of Kaivopuisto, Kruunuvuorenselä has had 500 such cormorants fishing in recent days. Similarly, there are about 500 individuals east of Santahamina, ”says the researcher Pekka Rusanen About the Finnish Environment Institute.
In Espoo along the shoreline in the area of Matinkylä and Suomenoja, cormorants can often be seen sitting on islets a stone’s throw from the shore. However, according to Rusanen, cormorants do not nest on these small islets, but they are just so-called resting islets, which are used by cormorants during migration trips, among other things.
The nearest nesting sites can be found, for example, in Helsinki’s Old Town Bay and in the outer archipelago of Espoo in front of the Summer Archipelago. This year there were an exceptional number of nests in Espoo, as many as 800. That is twice as many as last year.
However, the cormorant population in the Gulf of Finland has leveled off after a long period of continued growth. There are almost 40,000 individuals in the Gulf of Finland, including fry, before the start of the autumn migration.
“Nothing can multiply indefinitely. The denser the cormorant population, the more regulatory factors emerge. The sea eagle has increasingly begun to vaccinate the population. So there is no need to worry that the number will explode. We have already experienced that pin, and the situation has now remained fairly stable for the last few years. ”
About passers-by it may seem that cormorants are now remarkably abundant in the urban environment. However, the phenomenon is not exceptional, but is related to the autumn migration period.
Cormorants nesting in Finland overwinter in Central Europe and the Mediterranean. Moving south will start as early as July-August, and by November only a small portion will remain. Along the way, they may congregate in even large flocks in their moods. Some individuals can now be seen up to a few meters from the beach.
“And they don’t terrify people terribly, even though they are shot quite wildly in the wintering areas in the south. Admittedly, many of these sitting near the beach are young birds – chicks this summer. They don’t know about the hustle and bustle of people yet and may be a little silly. You can just see them in a bit of weird places. ”
This year, the cormorant has not been in a hurry for warm latitudes.
“Quite a lot of them are still here. Maybe they’ve been left waiting for the right moment, or the fish are fine for some reason. Yes, they are slowly figuring out here that the landscapes should be changed now. However, small amounts of them will sag even in winter if the places do not freeze. ”
Cormorant is a bird that many hate. The main reason for this is the harm caused by bird droppings. A cormorant that eats only fish for food frosting its nesting and resting islets with white feces. The feces are rich in phosphorus and nitrogen, and the islands of the communities that nest in cormorant trees are identified by dead white tree ghosts.
White-colored nesting islands and resting islets are considered ugly by many cormorants and are therefore not desired near their own cottage or home.
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If you belong to this above-mentioned group and are worried about the views of Kaivopuisto beach, Espoo waterfront or Kuninkaanlahti, for example, you can sigh with relief, according to Rusanen. The islets in these areas are just resting places for cormorants and the white color dims with the autumn and winter rains.
For many for humans, however, cormorants are only a natural part of the environment, and whitewashed islets are not considered a problem. Some species also benefit from it.
For example, a strong cormorant can defend itself against mink, among other things, and the bird can act as a security guard on nesting islets. For example, according to Rusanen, feeding birds like to join forces with the cormorant because of its protective effect.
Nutritious feces also act as a fertilizer in the soil.
“The flowering and meadow vegetation exploited by pollinators and butterflies often thrives on the edges of cormorant nest clusters.”
What about that pose mentioned at the beginning – why does a cormorant sit with its wings wide open?
“This is a question of eternity for which many explanations have been offered.”
One theory is that cormorants enhance digestion with posture. The second is that the cormorant communicates in such a way to its fellow species that good fishing waters have now been found. Namely, hunters have noticed that using cormorant-looking decoys with wings wide apart will attract other cormorants to the scene.
“Personally, I consider perhaps most likely the theory that the cormorant would sit that way because it dries the feather suit. But go and know. It could be that they let their friends know that it’s worth coming here. ”