Marek Panek

Conservation of farmland birds faces different challenges in Western and Central-Eastern Europe

Abstract. Birds are commonly used as an example of the strongly declining farmland biodiversity in Europe. The populations of many species have been shown to suffer from intensification of management, reduction of landscape heterogeneity, and habitat loss and fragmentation. These conditions particularly dominate farmland in the economically well developed countries of Western Europe. Currently, the farmland environment in Central-Eastern Europe is generally more extensive than in Western Europe and a larger proportion of people still live in rural areas; thus generating different conditions for birds living in agricultural areas. Furthermore, the quasi-subsistence farming in much of Central-Eastern Europe has resulted in agricultural landscapes that are generally more complex than those in Western Europe. To protect declining bird populations living in farmland, detailed knowledge on both species and communities is necessary. However, due to scientific tradition and availability of funding, the majority of studies have been carried out in Western Europe. In consequence this provokes a question: are findings obtained in western conditions useful to identify the fate of farmland bird biodiversity in Central-Eastern Europe? Therefore, the major goal of this paper is to highlight some local and regional differences in biodiversity patterns within EU farmland by comparing intensive agricultural landscapes with more extensive ones. More specifically, we aim to outline differences in agricultural landscapes and land use history in the two regions, use farmland birds to provide examples of the differences in species dynamics and species-habitat interactions between the two regions, and discuss possible social and ecological drivers of the differences in the context of biodiversity conservation. Factors governing spatio-temporal dynamics of farmland bird populations may differ in intensive and extensive landscapes as illustrated here using the Grey Partridge Perdix perdix and the Red-backed Shrike Lanius collurio as examples. The unevenness of farmland bird studies distribution across Europe was also presented. We call for more emphasis on pluralism in furthering both pan-European research on farmland bird ecology and conservation strategies. We also highlight some features specific to Central-Eastern Europe that merit consideration for the more efficient conservation of farmland birds and farmland biodiversity across Europe.

Selectivity of harvesting differs between local and foreign roe deer hunters : trophy stalkers have the first shot at the right place

Harvesting represents a major source of mortality in many deer populations. The extent to which harvesting is selective for specific traits is important in order to understand contemporary evolutionary processes. In addition, since such data are frequently used in life-history studies, it is important to know the pattern of selectivity as a source of bias. Recently, it was demonstrated that different hunting methods were selected for different weights in red deer (Cervus elaphus), but little insight was offered into why this occurs. In this study, we show that foreign trophy stalkers select for larger antlers when hunting roe deer (Capreolus capreolus) than local hunters, but that close to half of the difference in selectivity was due to foreigners hunting earlier in the season and in locations with larger males. The relationship between antler size and age was nevertheless fairly similar based on whether deer was shot by foreign or local hunters.

Red foxVulpes vulpes density and habitat use in a rural area of western Poland in the end of 1990s, compared with the turn of 1970s

The red foxVulpes vulpes (Linnaeus, 1758) density and habitat use were studied in open farmland of western Poland, where forests covered only 6% of the area. During 1997-2000, nocturnal spotlight counts (in spring and early winter), the location of breeding sites and snow tracking were carried out, and the feeding habitat was described based on the stomach content of shot individuals. The average fox density estimated on the ground of spotlight counts was 1.02 individuals/km2 in spring and 1.63 ind./km2 in early winter, while the winter density obtained from the results of track counts was 1.26 ind./km2. The average breeding population density, calculated as the double density of breeding sites (mean 0.31/km2), amounted to 61% of the average total spring density, which indicates the occurrence of surplus individuals in the population. The searching intensity of farmland by foxes did not changed with the increasing distance from forests, but relatively larger number of individuals was observed <0.5 km than 0.5–1.0 km away from settlements. Out of 81 identified breeding sites, 17% were located in forests and 83% in farmland. The predominant ingredients of the fox’s diet were farm livestock and small rodents (44.4 and 43.8% of the stomach content volume, respectively). The fox density in the study area was 5.4 times higher, compared with the turn of the 1970s, and changes in the habitat use consisted of more intensive occupation of open farmland and the use of human-produced food. Thus, these changes may have been among reasons of the increase in the fox density in western Poland.

Remex growth and body mass of mallards during wing molt

-We captured, banded (n = 4,129), and weighed (n = 809) Mallards (Anas platyrhynchos) during wing molt in western Poland. The condition of remex development was assessed (n = 3,421). We recaptured and remeasured 248 birds. The rate of remex growth in males (calculated by two methods) was 6.7 and 5.5 mm/day (P < 0.02). Males regained flight capability in 22-29 days, when remiges had reached 75-83% of final length. During the flightless period, males and females lost 12% of body mass. Birds whose flightless period was extended to replace only a few damaged quills continued to decline in body mass, which indicates that rate of mass loss was unrelated to costs of feather synthesis. We conclude that decrease of body mass is related to constraints on foraging time. We think this is a response to high exposure to predation during foraging. Reduction of flightlessness seems to be realized by a high growth rate of remiges, which was almost constant and independent of body mass. Received 24 August 1988, accepted 25 September 1989. LIKE other waterfowl, Mallards shed all their primaries and secondaries simultaneously, and are flightless during the period of wing molt. Flightless birds are more susceptible to predation, and movements are constrained. This situation influences habitat selection, antipredator behavior, foraging, and energy budget. Body mass decreases and body composition changes during flightlessness. Several hypotheses attempt to account for the changes in body mass. Hanson (1962) concluded that remex molt is a period of great nutritional stress for Canada Geese, and birds must catabolize body tissues to build feathers. Ankney (1979) argued that flightless geese can meet their nutrient requirements from the diet, and that maintenance of a superfluous reserve would be a waste of energy. Decreased body mass during molt may be adaptive, because it enabled birds to fly before completing growth of remiges, and this reduced the flightless period (Douthwaite 1976, Dean and Skead 1979, Owen and Ogilvie 1979, Bailey 1985, Austin and Fredrickson 1987, Sjoberg 1988). Young and Boag (1982) suggested that ducks may lose feeding opportunities as a result of secretive behavior. Douthwaite (1976) suggested that reserves accumulated before the molt make birds less vulnerable to food shortages where they would be exposed to predators. These hypotheses are not mutually exclusive, and Pehrsson (1987) suggested that limitation of foraging and use of body reserves minimalize exposure to predation and simultaneously shorten flightlessness. STUDY AREA AND METHODS This study was conducted in the floodplain of the River Warta at its confluence with the Odra River, western Poland (Majewski 1986). Flightless ducks concentrate in willow bushes (Salix spp.) surrounded by shallow water. The number of male Mallards that molt here reaches 25,000, many times greater than the number of local breeders. In 1981-1982 flightless Mallards were surrounded and driven into a net enclosure (Majewski 1981). Birds were banded (3,788 males and 341 females), weighed to the nearest 20 g (640 males and 169 females), and the ninth primary was measured to the nearest 1.0 mm (3,143 males and 278 females). The birds were then released. We recaptured 337 males and 13 females, typically after 3-9 days. Each was remeasured. Because most females were trapped late in the season, there were relatively few recaptures. We calculated the rate of remex growth from differences between lengths of the remiges divided by number of days between capture and recapture of each individual (n = 237). Birds with broken or pulled remiges were excluded, but some damage to remiges might have been overlooked. When caught for the first time, some birds shed their remiges, but regrowth was not yet visible. Recapture of these birds (n = 12) provided remex growth rates from the beginning of feather replacement. The remex length required to resume flight was established from the longest primaries among captured birds. We assumed that birds capable of flying could not be captured. We measured final length of the ninth primary in 18 males and 50 females caught or shot in other seasons. We estimated duration of flightlessness from the growth rate of remiges. Changes in body mass during molt were calculated 255 The Auk 107: 255-259. April 1990 This content downloaded from 207.46.13.101 on Sat, 08 Oct 2016 05:49:11 UTC All use subject to http://about.jstor.org/terms 256 PANEK AND MAJEWSKI [Auk, Vol. 107

The effect of experimental removal of red foxesVulpes vulpes on spring density of brown haresLepus europaeus in western Poland

Red foxesVulpes vulpes (Linnaeus, 1758) were experimentally removed in two nearby areas located in western Poland to verify the hypothesis about the limiting impact of their predation on the low-density population of brown haresLepus europaeus (Pallas, 1778) (4.4-10.6 ind./km2 in late autumn). In 1996/1997–2001/2002 foxes were culled (mainly in autumn and winter) in the reduction area (32 km2), whereas in the control area (34 km2) intensive culling was carried out only in 2000/2001–2001/2002. Indices of fox and hare spring densities were estimated using spotlight counts, as mean numbers of individuals observed per 10 km of the counting route. Annual changes in the fox density indices were negatively correlated with the bag of foxes, and annual changes in the hare density indices were negatively related to the annual changes in fox density indices. The fox density indices were significantly lower in the reduction area than in the control one only in 2000–2001 (2.8 times, on average), and in the same years, the hare population responded with higher density (1.7 times, on average). The hare responses took place without time delay, which suggests that the changes in fox abundance affected the situation of hares primarily in the autumn-winter season.

The relationship between hunting methods and sex, age and body weight in a non-trophy animal, the red fox.

Recently, hunting has represented a major source of mortality in game animals, including red fox, Vulpes vulpes, populations. Data from hunting studies have been used to explain evolutionary changes (body size, dental structure) in fox populations; however, knowledge of potential sources of bias in these kinds of data is lacking. Moreover, nature and game managers as well as conservationists have recently been seeking methods to limit European fox populations, which are increasing. In the present study in Polish farmland, we show that three different hunting methods (individual – lying in wait, with dogs at dens, with beating undergrowth to flush out foxes) resulted in differences in the age, sex ratio and body size of shot foxes. Taking account of seasonal differences in hunting methods used, shooting assisted by beating gave a higher proportion of male foxes, whereas individual hunting resulted in smaller foxes in shot samples. Hunting with dogs resulted in heavier female foxes, with the results being skewed towards females. Thus, this method may help limit the breeding capacity of a population and is recommended to assist in the control of red fox populations, at least in farmland areas.

Autumn–winter diet of Grey Partridges Perdix perdix in winter crops, stubble fields and fallows

Capsule Diet composition differed significantly between winter cereals, winter oil-seed rape, stubble fields and permanent fallows. Aims To determine the composition of the diet of Grey Partridges in autumn and winter in four agricultural land-cover types, characteristic of lowland areas of Central Europe. Methods Faecal analysis was used to determine diet. Multivariate analysis of variance (manova), Simpson Index of Diversity (sid) and Detrended Correspondence Analysis (dca) were used to assess variation in the proportions of the six main dietary components (cereal and broad-leaved plant leaves, weed seeds cases, cereal grains, husks of grasses and other plant material). Results Thirty-seven different kinds of plant food items were found, and the most numerous were cereal leaves (58.2% in total of all items), followed by leaves of broad-leaved plants (21.8%), weed seed cases (13.3%), cereals grains (3.5%), husks of grasses (1.2%) and other plant material (2.0%). Diet composition differed significantly between winter cereals, winter oil-seed rape, stubble fields and permanent fallows. The dca showed that the two first axes explain 38% of the total variance of the diet. The diet diversity was highest in stubble fields and permanent fallows, and the smallest in winter cereals. Dietary diversity was negatively correlated with the overall abundance of leaves, and positively with the abundance of weed seeds, cereal grains and husks of grasses. Conclusion Cereal leaves might replace other food items, which suggests that food resources are not a critical factor limiting the population of Grey Partridges during winter. A high proportion of weed seeds and cereal grains in the diet of Grey Partridges in stubble fields confirms the importance of these fields as sources of food of high-calorific value. Maintenance of stubble fields and cover crops with natural regeneration of annual weeds should constitute an important element of a strategy for the recovery of Grey Partridge populations in arable landscapes in Europe.

The effect of oilseed rape occurrence on main prey abundance and breeding success of the Common Buzzard Buteo buteo

Capsule The occurrence of oilseed rape increased main prey abundance and breeding success of Common Buzzards. Aims We tested whether the occurrence of oilseed rape influences the abundance of Common Voles, i.e. the main prey of Common Buzzards and so also nesting activity and breeding success of Common Buzzards. Methods The study was carried out in 2005–2012 in a 38 km2 area in western Poland, where oilseed rape plantations (12–106 ha) covered 18% of the agricultural land. The number of active burrow entrances was used as an index of vole abundance in various crops, and Buzzard breeding performance, i.e. the occurrence of annual nesting attempts in individual long-term nesting sites as well as the presence and number of fledglings, was estimated by observations of their nests. Results The index of vole abundance was highest in oilseed rape, and judging by the proportion of active burrow entrances (33–77%), the plantations of rape typically supported a larger portion of the local vole population than other crops. The acreage of oilseed rape fields around individual nesting sites of Buzzards did not affect the probability of nesting attempts in these sites. However, the probability of successful nesting and the number of fledglings per successful nest increased with the area of oilseed rape around the Buzzard nesting sites. Conclusion The occurrence of oilseed rape may positively affect prey availability and in turn the breeding success of Buzzards. The spread of oilseed rape may therefore also be beneficial for other vole-eating raptors hunting in the agricultural landscapes.

Does handling reduce the winter body mass of the European hare

Winter body mass of the European hare Lepus europaeus Pallas 1778 was analyzed with a special focus on changes induced by handling. Data were obtained from large scale translocation (net catchments) during 1960–1980 in Poland. The influence of handling was compared using the mass of first-time captured and repeatedly-captured hares, and, in case of repeated capture, individuals’ mass changes were investigated. The average body mass ranged from 2.1 kg to 5.0 kg. Generally, fewer factors influenced the hare’s body mass than expected. Body mass was related to age and winter precipitation, while the date of catching, sex and temperature did not have an effect. Body mass of first-captured hares were significantly higher than the re-captured ones (3.99±0.42 vs. 3.88±0.48, mean ±SD). Body mass change between captures was related to the date of the first capture, and the duration between the first capture and re-capture. Following the initial capture, a slight (2.8±2.6), but significant decrease in body weight occurred. Thus, the handling of hares should be used with caution during studies or management of the species.

Habitat use by the Partridge Perdix perdix During the Breeding Season in the Diversified Agricultural Landscape of Western Poland

Abstract. The study was carried out in 1994-96 in an area of western Poland where field sizes range widely —from < 1 to 50 ha. The spring population density of Partridges was estimated by call counts on 1 km2 study plots. The landscape structure was described by the proportion of crops and orchards, the number of arable fields and the length of permanent cover with spontaneous vegetation. Radio-tagged individuals (24 pairs and 6 single males) were tracked during the breeding season. The Partridge density in the study plots ranged from 0 to 7.7 pairs per km2, and increased with the number of fields per km2 and the proportion of small orchards among the arable fields. Radio-tagged pairs on small fields (< 10 ha) preferred field edges with permanent treeless plant cover and edges without permanent plant cover. On large fields (> 10 ha), a preference was shown for field edges with both wooded and treeless permanent plant cover. Partridges avoided the centres of both types of fields. Preferred nesting sites were in permanent plant cover and orchards; crops were used less frequently than expected. The spring carrying capacity of the field habitat for Partridges was dependent on the availability of field edges, including those devoid of permanent plant cover.