Monday, May 21, 2007

Merganser Research in the Lazovsky District (May 11-17, 2007)

Back in March one of the Institute of Marine Biology’s education specialists, Liliya, introduced me to a friend of hers, Diana Solovyova. Diana is a scientist at Wrangel Island Zapovednik (nature reserve), located way up north in the Arctic Circle. She studies marine ducks. Every year since 2001 Diana has come to the Lazovsky District, located about 200 km north of Vladivostok, together with her husband, Sergei, to study a rare duck species, the merganser (Mergus squamatus; in Russian, чешуйчатый крохаль). (Sergei is actually a geographer and expert on mammoths! He also works at Wrangel Island, and he and Diana have been working in the zapovednik system, and particularly in the Arctic, for their entire professional careers.)

Diana is super, and back in March she agreed that I could come spend some time with her and Sergei in the field. So I took my second trip out to Lazovsky District in mid-May (this time it was much greener than in mid-April!), and I not only got a chance to see Diana and Sergei’s work in the field, but also to talk with them about everything from science to education to politics to the zapovednik system. They are both fantastic people, and I had a great time.

About Mergansers and Diana’s Research

Mergansers are a rare species found only in the Russian Far East and Northern China; they winter in Korea and China. Nobody is exactly sure how many of these ducks there are left in the wild; estimates range anywhere from 2,000-10,000 individuals. 80% are in the Russian Far East. Why, you may ask, are scientists from the Arctic’s Wrangel Island studying this bird in the Russian Far East, when mergansers don’t travel to Wrangel Island? It turns out that if you study marine birds and you work in the Arctic, like Diana, you don’t have too much to do in the field before June, when the birds start to arrive for the summer. The Ministry of Natural Resources, which pays all zapovednik employees, is okay with employees from one zapovednik doing work in another zapovednik (in this case, Wrangel Island employees doing work for Lazovsky Zapovednik), as long as they’re not busy in their own reserve.

Because Diana does work on marine ducks, she has worked not only in the Russian Arctic but also in the places these birds migrate to – the U.S. (Alaska) and Northern Europe. She also knows English very well. Mergansers are an IUCN (World Conservation Union) Red Book Species (meaning they’re rare), so there is a lot of international interest in studying them, and people approached Diana. Since 2001 the research she leads on mergansers in the Primorye Region of the Russian Far East has been stably supported by a number of grants (from US Fish and Wildlife Service, etc.).

The location: Diana and Sergei work in 4 adjacent districts in the Primorye Region, but they do most of their work in the Lazovsky District. The field season: late March to late May. The last two years they have rented a house in Kishenyovka, a village of 240 people located in the Lazovsky District on the border of Lazovsky Zapovednik. (Diana estimates that of these 240 people, maybe 5 of them are employed. The rest don’t really seem to want to work, and how they spend their time was beyond Diana and Sergei. Obviously, they are a threat to the zapovednik, since they can easily cross into the territory and illegally fell trees, collect herbs, etc.)

The science team: Diana, Sergei, their field and equipment assistant, also Sergei, and Diana and Sergei’s very happy 3-year-old black lab, Joy, are constantly together. Valery Shokhrin, a Lazovsky Zapovednik scientist who is a specialist on predatory birds, also often joins them in the field. And then they have visitors like me, or like Tony, a marine birds specialist from Denmark who spent a couple of weeks in the field with Diana this year in late March-early April.

Mergansers nest in tree hollows on river banks, and a big part of Diana’s research focuses on studying places with changes in habitat, where trees along the river may have been chopped down. In the Lazovsky District a decent amount of forest along the rivers has been logged, and one hypothesis is that now there may not be enough nesting sites for mergansers here. Therefore Diana and Sergei have been putting artificial nests about 20 feet high up in trees since 2001. (These artificial sites either look just like wooden boxes, or like cylinders or wooden “tubes”.)

Sergei and Diana have placed a total of 140 of these artificial nests throughout the 4 districts where they work, with 45 in the Lazovsky District. In the Lazovsky District they find that about 30% of their artificial nests get used every year, and they assume that there are enough natural nesting sites for the rest of the birds. In the Olginsky District, for example – another of the 4 districts where they work – they find that only 5% of the artificial nests get occupied. Here there is just as much logging of the river banks as in the Lazovsky District, but there are not as many mergansers, so apparently fewer sites are needed.

Organizing the Field Season

Field work in late March starts with cleaning the artificial sites of litter and debris collected during the year, and in March and April Diana begins counting and tagging the adult birds as they return to the rivers of the Primorye Region. They catch the birds by putting nets up across the rivers.

At the end of April they start checking their artificial nesting sites to see if birds are using them. The also check the natural nesting sites that they know about. However, it is very difficult to find natural nesting sites, and they have only found 5 or 6 so far, all in the Lazovsky District, where they spend most of their time. (You have to spend a significant amount of time in a place to find the natural nesting sites – suitable little tree hollows are not necessarily easy to discover.)

Maybe you guessed it – checking the nests (and also putting up artificial nests) involves climbing trees. Sergei is an excellent tree climber. When they do the first check of nesting sites starting at the end of April, if they find a nest and a mother, they don’t catch and tag the mother at this time. This is very important! If there is a mother in the nest, she has most likely just recently laid her eggs. If they were to catch her, she would probably abandon the nest. Therefore they wait to catch and tag the mother until after she has made a significant commitment to the nest and won’t abandon it. During this first check, if a mother is there she will just fly away. Then Sergei will take out the eggs. They count the eggs and record the size and weight of each of them.

They also do a water test to determine how old the eggs are. They take an egg and put it in a jar of water. Eggs laid more recently are heavier and will stay at the bottom, where as older eggs are lighter and will float. They can actually estimate how many days old the eggs are. The eggs take 31 days to hatch, and therefore from the water test Sergei and Diana know by approximately what date the ducklings will hatch and, consequently, by what date they have to come back and catch the mother. (They have to catch the mother before the eggs hatch). Mergansers are like chickens – when they hatch, they are ready to go, and one day after their birth the mother will already have them out of the nest and on the water. They’re not like the typical songbirds in your backyard that spend a bunch of time in the nest getting fed by their mother after being born.

When I got to Lazovsky District on May 11 Diana and Sergei were at the stage of doing the second round of checks of their nesting sites. (I really hoped I might get to see ducklings! But the earliest would not start hatching until I was already getting ready to leave Lazovsky District.) From their late-April check Sergei and Diana already know at which sites there was a nest, and now it was late enough to catch the mother birds at those sites. At the same time the teams also does a second check of all the nesting sites, because it’s possible that a mother just hadn’t nested yet when they checked the first time around in late April. Sergei said last year they found a lot of new birds when they checked the second time around, but this year they have not found hardly anything – no mergansers, and just one mandarin duck nest in the Lazovsky District.

On my first day we went to an artificial nest where Sergei and Diana knew there was a mother and caught her. To do this Sergei (standing on the ground) puts a big net that is on a long pole up to the mouth of the nest; the bird senses a disturbance and flies out into the net. (Obviously, you have to be very quiet when you approach the nest.) Sergei and Diana had caught this mother already last year, and they had not only tagged her but also put a logger on her. The logger reads data about the bird’s surrounding environment (things like salinity, temperature, light and dark, etc.) every ten minutes nonstop, all year long. The loggers were used for the first time last year, and they put them on 8 birds. Nobody really knows where the birds go after they leave the Russian Far East for the winter, so they hope these loggers will provide a lot of useful new information. This was the second logger that they had managed to recollect this year for analysis.

Sergei and Diana weighed the bird, took off the logger and put a new one on her, and clipped a sample of her feathers from under her wing. This sample will be used to do a stable isotope analysis, which should help provide information about the time the bird spends at sea versus in fresh water environments. (Although no one can be certain that mergansers migrate to the ocean in the winter, it is generally assumed that they do.) This bird was incredibly calm; I was amazed.

Later in the afternoon we checked another artificial nest, this one in the shape of a box, rather than a tube. There were two mandarin duck eggs in it, which Diana weighed and measured. Interestingly, mandarin ducks lay one egg every day, usually for a total of about 10 eggs. (Since mandarins and mergansers often use similar nesting sites, Diana and Sergei take data on the mandarin ducks they find in their artificial nests, too. Generally mandarins prefer the boxes, mergansers the tubes, although both use both types.) Mergansers usually lay 10-11 eggs. Usually all of them hatch, but only about 60% then live after the ducklings move out to the river, as they get eaten by predators like eagles and mink. In the first winter it is likely that another 50% die, assuming they move out to sea, as the transition from a freshwater to a marine environment can be a tough one.

Mergansers often return to the same nesting site to hatch, but they’re not like salmon, so this is not required – they can certainly go to new places, although no one is sure how likely a scenario this is. However, Sergei and Diana have been concerned that in the course of their 7 years of work here, they have only come across the same birds (which they can identify because they have tagged them, of course) for 2 or at best 3 years in a row – and then they don’t see them again. This makes them think that mergansers may have a high mortality rate. Mergansers can live about 10-12 years and reproduce at 2-3 years. They survive well in captivity, and in Europe many are now being raised and studied in captivity. As you may have gathered, not enough is known about this rare bird – how many there are, where they migrate to, and more. Some research on mergansers using artificial nesting sites was done in the Russian Far East, and in the Lazovsky District, in the 1970s and 1980s. So Sergei and Diana’s work is not only really interesting and professionally done, but also very important.

Pictures: 1. Diana’s husband Sergei holding a mother duck that was caught on my first day; 2. and 3. the village of Kishenyovka; 4. An artificial nest (cylinder); 5. Sergei is checking the contents of an artificial nest (this one box-shaped); 6. Diana carefully removes the caught mother bird from the net; 7. Sergei takes the logger off the bird; 8. Sergei and I winding up the tree climbing equipment after Sergei had checked a nest; 9. Educational posters about mergansers, which get put up in a number of places in Primorye (e.g., Lazovsky and Olginsky Districts, Vladivostok, etc.)

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