Mindaugas Dagys

Waterbird Populations and Pressures in the Baltic Sea

This report outlines the results of the internationally coordinated census of wintering waterbirds in the Baltic Sea 2007-2009 undertaken under the SOWBAS project (Status of wintering Waterbird pop ...

Bird Bycatch in Fishing Nets in Lithuanian Coastal Waters in Wintering Season 2001–2002

Bycatch of birds wintering in Lithuanian coastal waters in gillnets was investigated in the wintering season 2001–2002. Vulnerability of different bird species to entanglement in fishing nets as well as threat posed by nets of different mesh sizes to birds were identified. Stellers Eider and Redthroated and Black-throated Divers were found to be most threatened by inshore gillnet fisheries. Nets of larger mesh sizes, particularly salmon nets (>60 mm mesh size) pose the greatest threat to wintering birds. The most urgent bird conservation measures are proposed, and the possibility to manage inshore fisheries in bird-friendly manner with little adverse effects on fishermen community is discussed.

Recent Changes in Distribution of Wintering Populations of Waterfowl Established on the Basis of Lithuanian Ringing Recoveries

Recent changes in the wintering grounds of the Lithuanian breeding population of Mute Swan, Mallard, Common Pochard, and Coot were established by means of the analysis of the long-term ringing data stored in the Data Bank of the Lithuanian Bird Ringing Centre. Significant changes in the wintering grounds of Mute Swan and Mallard of the Lithuanian breeding population have occurred since the late 1980s; the wintering grounds of Common Pochard and Coot, on the other hand, have changed just unremarkably. These changes were primarily caused by human impact and an increased number of mild winters during the present climatic amelioration.

WINTER PERIOD ORNITHOLOGICAL IMPACT ASSESSMENT OF OIL RELATED ACTIVITIES AND SEA TRANSPORTATION IN LITHUANIAN INSHORE WATERS OF THE BALTIC SEA AND IN THE KURŠIŲ LAGOON

Abstract Studies carried out during the last decade indicated that a number of key wintering sites of waterfowl and seabirds of NW Europe arc located in brackish waters of the Baltic Sea. Experience of many industrialized countries shows that human activities are likely to cause harm to waterfowl and seabird concentrations, especially in winter, when these birds aggregate in high numbers and become very susceptible to any human impact. The increase of oil related activities and sea transportation in the eastern Baltic in general and in Lithuanian waters in particular gave rise to concern about the well-being of birds wintering in Lithuanian waters. The current study was carried out in order to assess the magnitude and significance of negative impacts of oil related activities, at present and in the future, on wintering waterfowl and seabirds in Lithuanian inshore waters of the Baltic Sea and in the Kursū Lagoon. Information about the current level of oil related activities and their prospected development...

Changes in Numbers and Distribution of Wintering Waterfowl Populations in Lithuania in the 20th Century

Changes in numbers and distribution of wintering waterfowl populations in Lithuania in the 20th century are assessed and their reasons analysed. A total number of wintering waterfowl species increased from 17 in the 1900s–1940s to 28 in the 1960s and to 42 in the 1990s. A total number of wintering wildfowl species doubled. In the 1930s, several thousand wintering waterbirds were recorded throughout the Lithuanian wetlands. In the late 1990s, about 150,000 wintering waterbirds were annually counted on coastal wetlands and about 50,000 of them – on inland water bodies. Major changes observed in species composition and in the abundance of wintering waterfowl in Lithuania were primarily caused by the human activities affecting waterbird habitats and by general climatic amelioration, an increased number of mild winters in the Eastern Baltic region in recent decades.

Breeding Performance, Apparent Survival, Nesting Location and Diet in a Local Population of the Tawny Owl Strix aluco in Central Lithuania Over the Long-Term

Abstract. In the present study, we used 37-year long dataset on Tawny Owls from the annual monitoring of nestboxes at a sample plot in Central Lithuania. We expected that Tawny Owls responded to changes in land use practices, stemming from a change in both political and economic system, which may affect prey abundance and composition, breeding performance and demography. To analyze temporal changes in monitored parameters, we divided the study period into three phases (1978–1989, 1990–2001 and 2002–2014), corresponding to different socio-economic conditions. The number of nesting pairs of Tawny Owls decreased significantly in the last 13 years of the study, but the number of successful pairs fluctuated without any trend. The clutch size and number of nestlings varied without significant trends, but nesting success improved over the last 13 years. Annual apparent survival probability of the female Tawny Owls did not vary significantly over the study period (model averaged values between 0.71 and 0.73). Owls occupied nestboxes irrespective to the distance from the agricultural land during the first two study periods, but since early 2000s, owls tended to occupy nestboxes located deeper in the forest. Birds and small mammals were similarly important as prey items by biomass. Since the 1990s, the share of Microtus voles significantly decreased in the diet, while that of birds increased. In summary, changes in the diet, improved nesting success of the Tawny Owl and tendency of nesting in forest interior may indicate ongoing complex responses to the changes in environmental conditions.

POSSIBLE IMPACT OF GILL NET FISHING ON WINTERING BIRDS IN LITHUANIAN INSHORE WATERS OF THE BALTIC SEA

Abstract Spatial distribution and intensity of gill net fishing activities in Lithuanian inshore waters of the Baltic Sea were studied in the winter of 1996/97 in order to identify the possible impact of these activities on wintering birds. Internationally important waterfowl and seabird wintering site along the coast of Palanga was found to overlap with intensive gill net fisheries. Consequently, Stellers Eiders wintering in compact flocks in this site are most likely to be adversely affected by gill net fishing. Other abundant species in this wintering site—Red-throated and Black-throated Divers and Long-tailed Ducks may also be subject to considerable pressure from gill net fisheries. More detailed investigations are needed to quantify these impacts and assess their significance.

Adaptive habitat preferences in the Tawny Owl Strix aluco

ABSTRACT Capsule: Tawny Owls Strix aluco occupying nest boxes preferred habitats which were positively associated with the probability of nesting success. Aims: We aimed to determine whether or not: (1) Tawny Owls showed habitat preferences when occupying nest boxes; (2) nesting performance was related to the habitats around occupied nest boxes and (3) habitat availability had changed around available and occupied nest boxes between 1995–2004 and 2005–14. Methods: Tawny Owls were studied using nest boxes erected in a commercial forest. During nest boxes checks (724 cases), data on occupancy and nesting performance (88 cases) were recorded, and habitat within a 0.4 km radius around nest boxes was analysed. Results: Tawny Owls had preferences for clearings within forests, mature forests and grasslands but avoided young forests. We found a positive relationship between nesting success and abundance of clearings within the forest, and a negative relationship between nesting success and abundance of young forests. A change in habitat preferences over the two decades was evident, but habitat availabilities remained similar. Conclusions: Findings indicate adaptive habitat selection in Tawny Owls because preferred habitats were associated with higher fitness and this type of habitat became more frequently selected over time.

Long-Term Ecological Research Network in Lithuania

The network of sites with long-term ecological research (LTER) in Lithuania was initiated and organised by the Institute of Ecology of Vilnius University in 2004. Scientists from several research institutes and universities are engaged in implementing the scientific program of the network. The site-based long-term multidisciplinary ecological research has a central role in the network. The key research topics cover both abiotic and biotic components of ecosystems. Four sites have been designated for the LTER program in Lithuania: Lithuanian coastal area, Cepkeliai State Strict Nature Reserve, Kamanos State Strict Nature Reserve and Lake Drūksiai with adjacent wetlands. These sites are representative examples of ecosystems characteristic of different regions of Lithuania and have proper scientific background from earlier and ongoing multidisciplinary research. Cross-border sitebased ecological research has recently been initiated in LTER sites shared with Belarus and Russia. Certain research programs are i...