Differences in a Cage Escape Behaviour between Two Migrating Warblers of Different Stop-Over Strategy

Cognitive abilities play an important role for migratory birds that are briefly visiting a variety of unfamiliar stop-over habitats. Here, we compared cognitive abilities-linked behaviour (escape from an experimental cage) between two long-distant migrants differing in stop-over ecology, Sedge Warbler (Acrocephalus schoenobaenus; not territorial, searching for locally superabundant food) and Reed Warbler (A. scirpaceus; territorial, foraging on a common prey) during the autumn migration. After two minutes of acclimatization in the cage, we remotely opened the cage door and recorded the bird’s reaction. We measured latency that individuals needed to escape from a cage. Sedge warblers were 1.61 times more likely to escape from the cage than Reed Warblers. Sedge warblers generally escaped earlier after the door was opened and were 1.79 times more likely to escape at any given time than Reed Warblers. We interpret the prevalence of non-escaped individuals as a general feature of migratory birds. In contrast to resident species, they are more likely to enter an unfamiliar environment, but they are less explorative. We attributed inter-species differences in escape latency to species-specific autumn stop-over refuelling strategies in the context of specialist-generalist foraging. Our study provides ecological insight into the cognitive abilities-linked behaviour of wild animals.

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).

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.

Busse’s flat orientation cage vs. Emlen’s funnel – compatibility, differences and conclusions

This paper focuses on field practice using different types of orientation cages. The two orientation cage designs most commonly used in field work, i.e. Emlen’s funnel and Busse’s flat orientation cage, are described in detail and compared for compatibility of results, simplicity of use and time effectiveness. Apart from cage designs and field procedures (60-min nocturnal tests in Emlen’s funnel vs. 10-min diurnal tests according to Busse’s procedure), the standard data evaluation procedures are compared and discussed. The data used in the discussion were collected for four species of nocturnal migrants (the Reed Warbler, the Sedge Warbler, the Willow Warbler and the Whitethroat) at the Kalimok Bird Station (Bulgaria): altogether 141 individuals were tested in Emlen’s funnel in 2001 and 788 in Busse’s cage in 2001-2007. The following conclusions were drawn: (1) Busse’s flat cage design and its standard procedures yield results fully compatible with those obtained using Emlen’s funnel and the associated procedures; this means full compatibility in terms of the directionality of tested birds in the diurnal and nocturnal tests; (2) the procedures compared have distinct differences in terms of constraints on the methods: – Emlen’s cage is extremely stressful for the bird and should be avoided as much as possible in practice due to animal welfare concerns; – Emlen’s standard procedure of testing the bird for 60 minutes is completely useless, as this is inefficient in terms of quality of results and causes more stress to the bird than is necessary; – Busse’s 10-minute standard makes it possible to collect a vast amount of data (12 birds per hour and person) in real field work, even performed in wilderness areas; (3) At the stage of evaluation of raw data it is essential to use evaluation tools which take into account the fact that raw data items show a high percentage of multimodal distributions, and therefore tools assuming unimodal distribution are unsuitable.