One of the most common techniques to investigate bird migration is bird ringing. At Tauvo, a hamlet situated more or less 50km from Oulu, they started ringing at the seventies.
I got the chance to visit the station two times this autumn, so let’s go for a bit of storytelling!
RINGS, AN ID FOR BIRDS
Since 1899, birds became ringed for all kind of scientific purposes. It was the Dane Ch. Mortensen who started this by ring a hundred starlings to see which places they visit. In the following years, the technique became more and more popular. Nowadays, ringing birds is still one of the most used techniques to do research on the life of birds.
You can compare a bird ring with our ID. A ring contains a code which resembles our National Insurance number, and often also a code specific for the place where the bird became ringed. The disadvantage of a metal ring is that the bird needs to be recaptured before you can get useful information. To counter this problem partly, coloured plastic rings are often used. Neck rings and wing tags are also used on bigger birds (mostly geese and raptors respectively)
To ring birds, mist nets are needed. These nets are made of very fine mesh so that birds cannot see them. A ringer regularly checks these nets and then takes the captured birds for ringing and some measurements (wing/tail length, weight,…) after which the bird is released again.
Matti Tynjälä has been ringing birds in Tauvo since 1976, that is exactly 45 years! Matti started ringing in 1974 as part of his thesis. He couldn't let go of bird ringing ever since.
He doesn't really know why it keeps him so busy, it's a passion and that is difficult to express in words. Every spring he starts ringing again, no matter how difficult and frustrating it can be at some times. For example, too many times he had to re-hang nets because Moose had walked through them and destroyed them. Ringing birds in Tauvo just remains a high-class nature experience!
The mist nets are checked on a regular basis. After freeing the birds from the nets, they are placed in little dark bags pending the measurements.
Because birds are ringed, many questions about the existence of birds can be solved. How do birds migrate from the breeding grounds to their wintering ground? Which areas are important for these migratory birds? You can also check population dynamics. Which bird species are declining or expanding their range?
Matti especially notes a decline in species such as Willow tit (Poecile montanus) and Red-backed Shrike (Lanius collurio). Other species such as Blue Tit (Cyanistes caeruleus) or even Blue Tail (Tarsiger cyanurus) are improving. The causes differ, but the story of the Willow tit is interesting as this decline seems to be related to the rise of Blue tit and Great tit. The latter two seem to be expanding their habitat thanks to climate warming, the winters are becoming more and more liveable in the North.
Rustic Bunting (Emberiza rustica) is given a metal ring after wing length, tail length, weight and body fat percentage have been measured. After these measurements, the bird is immediately released.
Owls are also ringed in the evening at Tauvo. This mainly concerns Tengmalm's owl (Aegolius funereus) and to a lesser extent also Pygmy Owl (Glaucidium passerinum). We also hoped for Northern hawk owls (Surnia ulula) as there was/is an invasion of the west coast in Finland.
A total of 8 Tengmalm's owls were caught every evening and provided with a metal ring. This owl species can travel considerable distances when food is scarce. Recaptures are known from southern Norway.
Tengmalm's owls should be ringed with care because of their sharp claws. After the release, one of the owls kept an eye on the bird ring station for a long time.
WETLANDS, THE MC DONALDS FOR BIRDS
The bird ring station is located on the edge of a huge wetland called Ulkonokanhietikka. Here you will find a mix of birch storage, coastal grasslands and some (largely old) sand dune complexes. It sounds very unlikely, but land is being added to this region! In the past, during the ice ages, a thick pack of ice pressed the land. Since these ice caps have melted, the pressure on the land has disappeared and the land is rising about 8mm per year. As a result, numerous small islands are added off the coast. You can also see consequences of this in Tauvo. For example, when Matti started working here, he could still see the bare sandy beaches here. Due to the land uplifting, succession is now taking place and the drifting dunes are slowly becoming overgrown. During the years, Matti saw the area becoming more and more forested. Grazing with cows seems to be trying to empty the ocean with a thimble.
View from the tower at the ring station. Here you can see how the landscape changes from coastal mud flats to coastal grassland to birch storage with even pine trees here and there. Cows graze on the coastal meadows, but this does not seem to stop the succession.
The wetland is true Eldorado for birds. In the summer, species such as Dunlins, Redshank and numerous duck species breed here. During the migration periods (August - September and May) many birds enjoy a stopover here and the birds have a feast stocking up their bellies. I myself was a bit too late to experience the real trek. Nevertheless, we could still see some golden plovers, sandpipers, ringed plovers and a small sandpiper. Whooper swans and ducks also gathered en masse in the bay to get ready for the migration. Ducks also use this place to moult, they then change plumage and are therefore more vulnerable. White-tailed eagles (we saw four in one moment) then try to take advantage of this situation and score a tender bite. A hundred cranes graced the whole scene with their beautiful sound, heralding that they were leaving for the south.
Golden Plover (Pluvialis apricaria) in winter plumage with a Dunlin (Calidris alpina) looking for something tasty in the humid coastal grasslands. A White-tailed Eagle (Haliaeetus albicilla) is looking for a tasty bite.
THE LUXURY OF SLEEPING OUTSIDE ON A TOWER
Despite the fact that we had a super cozy building (including sauna!) at our disposal, I chose to sleep outside. I have to admit, the nights were quite cold. Hopefully the new sleeping bag (comfort -15°C) will help me a little better with keeping warm next time. The way I got a chance to wake up was definitely outstanding on the first morning. Around 7am, a group of whooper swans came flying (and called loudly) right above my sleepy head. The signal to get up full of energy and enjoy the breathtaking landscape.
What a way to wake up. Waking up in this environment gives you more energy than three cups of coffee!
I started looking for birds once I woke up with two French Erasmus students. We wanted to have a Black Grouse (Lyrurus tetrix) on top of a tree, or even better an owl! The morning started well with a Great Gray Shrike (Lanius excubitor). Sometimes a rather timid bird for the ringers as these birds dare to eat captured birds from the nets (just like ermines and many owls). The grouse didn't really cooperate, but after an hour of searching I got goosebumbs. I had just found my very own Hawk owl!
And that just when no one else was on the tower. Shit, hopefully the beast doesn't fly away. Calling names from the tower didn't really seem to be the best option to me, so I hoped that someone would check Watsapp quickly enough. About 5 minutes later, I heard the door close with a bang. The two Frenchmen ran up the tower - You should know that the wood was rotting here, I was a little scared - luckily the bird stays put, and we can enjoy it to the fullest (despite the distance). Too far for pictures but what a moment, the blurry mobile phone picture exactly how it was, a real kick! The fog moved inland from the bay, what a fairytale landscape!
Fortunately, we were able to use Matti's telescope to look for birds from the tower. At about 200 meters that this beautiful beast. An encounter that leaves you wanting more!
The fog is moved inland from the bay, what a dream! I was looking for something extra in the photo. Happy flying Whooper Swans (I love how these birds immediately give landscapes in Finland more cachet) criss cross the landscape!
My favorite photo so far. It summarises the ultimate nature experience for me. Waking up because of the rising sun and bird sounds!
In the previous blog I promised some more behind the scenes pictures, here's a picture of what a good evening looks like. Campfire, beer and music! Wonderful to be able to end fantastic days (and this blog) in nature like this!