Avifauna of meadow ecosystems in borderland areas of Lviv and Volyn Oblasts

Meadow ecosystems comprise a significant part of the area of Ukraine, especially in its western regions. Those ecosystems are subjects of concern today because of the active agricultural use and droughts that also threatens the animal population of meadows, including birds. Studies of meadow bird species of western Ukraine are limited to atlases, which results in a lack of precise data. This work was part of an international project on the conservation of the great snipe Gallinago media and allowed us to collect valuable data on the abundance and occurrence of meadow bird species nearby to the Polish and Belarusian borders of Ukraine — territories that are commonly ignored by Ukrainian researchers. The surveys of meadow birds conducted near the Ukrainian-Polish border in 2020 have shown that the general state of the marshes is worse compared to 2019: even close to the Western Bug river, only deep oxbow lakes were wet or contained some water, but minor lakes and wetlands of the valley were found to be dry. In total, we observed 141 bird species belonging to 17 orders. Among them, 26 were common by abundance and frequency, such as the great egret Ardea alba, the white stork Ciconia ciconia, the common quail Coturnix coturnix, the corn crake Crex crex, the northern lapwing Vanellus vanellus, the common redshank Tringa totanus, the common cuckoo Cuculus canorus, the Eurasian skylark Alauda arvensis, the meadow pipit Anthus pratensis, the western yellow wagtail Motacilla flava, the sedge warbler Acrocephalus schoenobaenus, the marsh warbler A. palustris, the great reed warbler A. arundinaceus, the common whitethroat Sylvia communis, the whinchat Saxicola rubetra, the thrush nightingale Luscinia luscinia, the common linnet Linaria cannabina, the corn bunting Emberiza calandra, the common reed bunting E. schoeniclus, and 7 more species, which were observed frequently though are not typical marshland species. We have identified the species that can be used as indicators of parameters of marsh ecosystems such as grass height (corn crake, western yellow wagtail, and sedge warbler), moisture (common redshank, common cuckoo, and the sedge and great reed warblers), and habitat type (corn crake, European bee-eater Merops apiaster, sedge warbler, common reed, and corn buntings).

Genomics of an avian neo-sex chromosome reveals the evolutionary dynamics of recombination suppression and sex-linked genes

ABSTRACTHow the avian sex chromosomes first evolved from autosomes remains elusive as 100 million years (Myr) of divergence and degeneration obscure their evolutionary history. Sylvioidea songbirds is an emerging model for understanding avian sex chromosome evolution because a unique chromosome fusion event ∼24 Myr ago has formed enlarged “neo-sex chromosomes” consisting of an added (new) and an ancestral (old) part. Here, we report the female genome (ZW) of one Sylvioidea species, the great reed warbler (Acrocephalus arundinaceus). We confirm that the added region has been translocated to both Z and W, and show that the added-W part has been heavily reorganised within itself and with the ancestral-W. Next, we show that recombination between Z and W continued after the fusion event, and that recombination suppression took ∼10 Myr to be completed and arose locally and non-linearly along the sex chromosomes. This pattern is inconsistent with that of large inversions and instead suggests gradual and mosaic recombination suppression. We find that the added-W mirrors the ancestral-W in terms of repeat accumulation, loss of genetic variation, and gene degeneration. Lastly, we show that genes being maintained on W are slowly evolving and dosage sensitive, and that highly conserved genes across broad taxonomic groups, regardless of sex-linkage, evolve slower on both Z and W. This study reveals complex expansion of recombination suppression along avian sex chromosomes, and that the evolutionary trajectory of sex-linked genes is highly predictable and governed partly by sex-linkage per se, partly by their functional properties.

Fast and furious: host aggression modulates behaviour of brood parasites

ABSTRACTAvian brood parasites pose a serious threat for hosts, substantially reducing their fitness which selects for the evolution of host defences. A classic example of a host frontline defence is mobbing which frequently includes contact attacking of brood parasites. Here, we investigated how the nest defence of a very aggressive great reed warbler (Acrocephalus arundinaceus) host influences the speed of egg-laying and egg-removing behaviour of its brood parasite – the common cuckoo (Cuculus canorus). We video-recorded 168 brood parasitic events at 102 active host nests and found that cuckoos avoided host mobbing in only 62% of cases. If hosts spotted the cuckoo at their nests, they almost always attacked it (in 91 of 104 cases), however, such attacks only rarely and temporarily prevented cuckoos from parasitizing (11 additional cases). When attacked, cuckoos parasitized host nests significantly faster and left them immediately. However, when not attacked, cuckoos frequently stayed at or near the nest suggesting that host aggression, rather than the risk of being spotted, influences the speed of brood parasitism in this species. Further, we found that cuckoos performed egg-removing behaviour in all parasitic events without regard to host aggression. As a result, cuckoos removed at least one egg during all brood parasitism events except those when an egg slipped from their beaks and fell back into the nest (in 9 of 73 cases). This indicates that egg-removing behaviour is not costly for the common cuckoo and is an essential part of its parasitism strategy, widening understanding of this currently unexplained behaviour.

Estimation of Local Heading Patterns of Nocturnal Migrants using Orientation Cages

Busse P. 2018. Estimation of local heading patterns of nocturnal Migrants using orientation cages. Ring 40: 31-58 The main aim of this paper is to compare the results of two data evaluation procedures used for presenting the data from the orientation cage field tests. Both procedures accept multimodality of the data and multimodality of the headings of an individual bird as well as migrating population. The goal is to reach acceptable level of migration patterns presentation in biological sense, taking under consideration a flexibility of the real movements, depending on specific weather and landscape parameters. Such knowledge is absolutely necessary for estimating migration bottle-necks and the long-term studies on influence of the climate changes on migration patterns. The material used for the comparison of the procedures was collected in years 2001-2007 by the team of the Bulgarian Ringing Station Kalimok (44°00’N, 26°26’E) within the frame of the SEEN (SE European Bird Migration Network) activity and kindly shared for evaluation. The data were obtained using the standard SEEN methods, with the standard Busse’s cage working procedure of the field tests. The material contains data on four species of nocturnal migrants living in different habitats: the Great Reed Warbler, Acrocephalus arundinaceus (ACR.ARU), the Sedge Warbler, A. schoenobaenus (ACR.ENO), the Willow Warbler, Phylloscopus trochilus (PHY.LUS) and the Whitethroat, Sylvia communis (SYL.COM). There are confirmed earlier conclusions that so called „classic” unimodal procedure is not applicable to the orientation cage data resulted from any field procedure. There are available two evaluation procedures that base on the same general assumptions: multimodality of distributions that reflects combination of several unimodal partial distributions, that can be described both using sophisticated Bayesian „Calculation” method and much simpler „Estimation” procedure. Results of both procedures are enough close to each other that they can be used for describing local and general heading patterns of migration of the nocturnal migratory movements studied using orientation cages.