Thursday, March 18, 2021

Amur Bird Project update: no fieldwork, but more publications

Amur Bird Project team at Muraviovka Park, August 2017

Due to the pandemic, no fieldwork was possible in 2020 (and perhaps not even in 2021) for the Amur Bird Project team in Russia. But we have made the best of it and published many of our findings!

In autumn 2017 we (Hans, Benny and Jonas) stayed at Muraviovka Park and spent several nice, creative weeks together. Here we like to remember those inspiring time and the unforgettable birds we saw and ringed. Now, more than three years later, each one of us has published a paper on his “own” project.

Hans, the moult enthusiast of our group, analysed data on the processes and variations of feather renewal of one of the characteristic species of our study area, the Pallas´s Grasshopper Warbler Locustella certhiola. Until recently assumptions on moult patterns for East Asian Locustella species were based on incomplete information. Based on data from six ringing sites situated along the flyway of Pallas’s Grasshopper Warbler from its breeding grounds in the Russian Far East to the wintering areas in Thailand detailed study revealed for the first time that in most individuals wing feather moult proceeds from the centre both toward the body and the wing-tip. This moult strategy is known as partial divergent moult (which is rare among Palearctic passerines). We found an increase in the mean number of moulted primaries during the progress of the autumn migration. Moderate body mass levels and low-fat and muscle scores were observed in moulting adult birds, without any remarkable increase in the later season. According to optimality models, we suggest that an extremely short season of high food abundance in tall grass habitats and a largely overland route allow autumn migration with low fuel loads combined with moult migration in at least a part of the population. This study highlights the importance of further studying moult strategy as well as stopover behaviour decisions and the trade-offs among migratory birds that are now facing a panoply of anthropogenic threats along their flyways.

Original publication:

Jonas, always attentive in the fine determination of unknown species, used the whole data set of bird ringing data obtained during several years of fieldwork by the many volunteers of the project to study the sex- and age- specific differences in the phenology of migrating songbirds. These differences in the timing of migration are widespread among animals. In birds, common patterns are protandry, the earlier arrival of males in spring, and age-differential migration during autumn. However, knowledge of these differences stems mainly from the Palearctic-African and Nearctic-Neotropical flyways, while detailed information about the phenology of migrant birds from the East Asian flyway is far scarcer. To help fill parts of this gap, we analysed the bird ringing data from our project to study how migration distance, sex, age, and moult strategy affect the spring and autumn phenologies of 36 migrant songbirds (altogether 18,427 individuals). Sex-differential migration was more pronounced in spring than in autumn, with half of the studied species (6 out of 12) showing a protandrous migration pattern. Age-differences in migration were rare in spring but found in nearly half of the studied species (11 out of 25) in autumn. These age effects were associated with the birds’ moult strategy and the mean latitudinal distances from the assumed breeding area to the study site. Adults performing a complete moult before the onset of autumn migration passed the study site later than first-year birds undergoing only a partial moult. This pattern, however, reversed with increasing migration distance to the study site. These sex-, age-, and moult-specific migration patterns agree with those found along other flyways and seem to be common features of land bird migration strategies.

Original publication:

Benny, with a keen eye for little, seemingly inconspicuous creatures, tirelessly motivated us to catch and collect louse flies from ringed birds. Recently he published the results. This was the first study about the louse fly fauna of the Muraviovka Park. We collected a total of 100 louse flies and recorded 91 breeding and migratory birds of 33 species being hosts. Furthermore, seven Hippoboscidae without assignment to a host were collected. To identify the louse fly species, we used a stereo-binocular microscope, a digital microscope and numerous literature resources. We also used DNA barcoding to explore if we find evidence for cryptic species within our data. Sixteen louse fly species are known from the Russian Far East. In our study we detected six of them, including one species with new taxonomic status, one species as a new record for the region, and two flies with divergent DNA barcodes. Flies of Ornithomya fringillina from Canada, Europe and the Russian Far East are located in the same barcoding cluster. For the most species presented in our study distribution maps are published. These maps show a gap between the Eurasian area in the west, up to the Ob River and Novsibirsk, and the Sichote Alin Mountains, eastern Manchuria, Japan and Korea in the east. The present investigations extend the western boundary of this isolated area in the easternmost part, and in the case of Ornithomya fringillina and Ornithomya chloropus our records suggest a gap closure between the eastern and the western distribution areas.

Original publication:

We thank all participants of the project, our co-authors and especially Wieland for the chance to visit such a special place and are very happy to share our results with you.  

Hans-Jürgen Eilts, Jonas Wobker and Benjamin Meißner