Numbers and distribution of Northern Lapwings Vanellus vanellus breeding in England and Wales in 1998

This paper presents the results of the BTO/RSPB survey of breeding Northern Lapwings Vanellus vanellus in England and Wales carried out in 1998. Numbers of breeding Lapwings and land-use types were recorded by volunteers in 1312 randomly selected tetrads using identical methods to those adopted in a previous survey in 1987. The results suggest a population of 62 923 breeding pairs (95% confidence intervals 55 268 to 74 499), representing a 49% decline in 11 years. The declines were greatest in southwest England and Wales, resulting in a marked contraction in range. Both arable and pastoral farmland was found to be important for Lapwings, highlighting their vulnerability to changes in a range of agricultural systems. Recent major changes in land management practices, including the switch from spring to autumn sowing and the conversion of rough to intensively managed, improved grassland is likely to have reduced both the area and the suitability of these habitats for Lapwings. Grassland within arable areas is known to provide important chick rearing habitat, and spring tillage with adjacent grassland was significantly more likely to hold Lapwings than spring tillage that did not abut grass fields. The prevalence of grass and spring tillage fields in close proximity has declined in recent years with the loss of traditional mixed farming and the polarization of pastoral systems in the west of Britain and arable in the east. The implications of these results for the conservation of Lapwings are discussed and it is recommended that, in the light of the scale of the decline recorded, Lapwings should be afforded much higher conservation priority in Britain than they are at present. The range contraction has resulted in high numbers being concentrated on reserves, highlighting the importance of sensitive management of these areas for this species. However, wider countryside measures should also be considered, such as specific options within agri-environment schemes, designed to enhance farmland habitats for Lapwings.     

Influence of environmental factors on the numbers and activity of wintering Lapwings and Golden Plovers

Variations in the numbers and activity of Lapwings Vanellus vanellus and Golden Plovers Pluvialis apricaria using 322 ha of lowland farmland were examined in relation to temperature, rainfall, wind speed and moonphase. The study was undertaken over two winters (1987/88 and 1988/89), with maximum counts of 4000 Lapwings and 820 Golden Plovers. Patterns of occupancy of the study area and seasonal occurrence are described. Temperature and the phase of the lunar cycle seemed to be particularly important in affecting the distribution and activity of the birds. More Lapwings occurred in the study area on the colder and on the wetter days in several months, and also around the full moon period when feeding activity was particularly prevalent. A higher proportion of Lapwings tended to feed on colder days and around the new moon period, while daytime loafing increased around the full moon period. These results support the ideas that birds need to feed more in cold conditions, when energy demands are high, and that night feeding frequently occurs during the full moon period, although the reasons for this remain unclear.     

Long-term trends in the abundance of breeding Lapwing Vanellus vanellus in relation to land-use change on upland farmland in southern Scotland

Capsule A long-term decline on this habitat is shown to be associated with the intensification of agricultural management, particularly the occurrence of field drainage.

Aims To assess long-term trends in the number of breeding Lapwing and determine the relationship between these trends and changes in agricultural management on an upland study area.

Methods Breeding Lapwing were counted along two road transects in nine years between 1980 and 2002, and on one extensive plot in 1980, 1990 and 2000. Counts along the road transects were made from a vehicle and the fields used for nesting were recorded. Changes in field management along the transects were monitored annually between 1980 and 1990, and habitat composition assessed in 1980, 1985, 1990 and 2000.

Results During the first 20 years of study the number of breeding Lapwing declined substantially on all three count areas and by 77% overall, with further declines on both transects in 2002. The area of unimproved grassland and arable on these transects also declined substantially due to conversion to improved grass. Fields that comprised either unimproved grassland or arable were most likely to hold nesting Lapwing, while the chance of a field losing its nesting Lapwing was positively associated with the occurrence of drainage. Drainage and conversion to improved grass were closely linked.

Conclusions Agricultural intensification is a probable cause of decline in the number of breeding Lapwing in upland areas. Such declines may have been widespread in upland areas following increased agricultural intensification in recent decades.     

Parental care,nestling growth and diet in a Spotted Eagle Aquila clanga nest

Capsule The breeding biology of the Spotted Eagle was studied and we analysed results from direct observations at a nest in Estonia.     

江西吉安灰头麦鸡的繁殖生态研究

灰头麦鸡Vanellus cinereus在江西吉安地区是夏候鸟.2010 ～2011年对当地灰头麦鸡的繁殖生态进行了调查研究.结果表明,当地灰头麦鸡最早2月20日迁入,最晚9月17日迁离,居留时间约为7个月;3月初开始产卵,平均窝卵数3.8枚(n=14),平均卵大小48.0 mm×34.5 mm,平均卵重28.8 g(n =38);产满窝卵后即开始孵卵,孵卵由雌雄鸟共同承担;孵卵期为28 ～31 d;孵化率为90.15％.     

Effects of hunting on the behaviour and spatial distribution of farmland birds: importance of hunting-free refuges in agricultural areas

Hunting is one of the human activities that directly affect wildlife and has received increasing attention given its socioeconomic dimensions. Most studies have been conducted on coastal and wetland areas and showed that hunting activity can greatly affect bird behaviour and distribution. Hunting-free reserves for game species are zones where birds find an area of reduced disturbance. We evaluated the effect of hunting activities on the behaviour and use of hunting-free areas of lapwings Vanellus vanellus , golden plovers Pluvialis apricaria and little bustards Tetrax tetrax in agricultural areas. We compared the habitat use and behaviour of birds on days before, during and after hunting took place. All three studied species showed strong behavioural responses to hunting activities. Hunting activity increased flight probability and time spent vigilant (higher on hunting days than just before and after a hunting day), to the detriment of resting. We also found distributional (use of hunting-free reserve) responses to hunting activities, with hunting-free reserves being used more frequently during hunting days. Thus, reserves can mitigate the disturbance caused by hunting activities, benefiting threatened species in agricultural areas. Increasing the size or number of hunting-free areas might be an important management and conservation tool to reduce the impacts of hunting activities.     

Declines of ground-nesting birds in two areas of upland farmland in the south Pennines of England

CapsuleWe present evidence of large declines in numbers of breeding waders and passerines in some upland areas since the 1970s.

Aims Changes in numbers of ground-nesting birds are documented for two areas of the Pennines and are qualitatively related to recent land-use history.

Methods Territory mapping was used to estimate bird numbers on two areas (76 and 99 ha) in the Pennines for which more than 10 consecutive years of data were available from the BTO's Common Birds Census archives.

Results At both sites there were large declines in Lapwing Vanellus vanellus, Snipe Gallinago gallinago, Skylark Alauda arvensis, Twite Carduelis flavirostris and Reed Bunting Emberiza schoeniclus. The two sites differed in the timing of the declines but for Twite the trends were almost identical. By the late 1990s, numbers of most ground-nesting birds were far lower than in the 1970s. There was relatively little change in numbers of species breeding at either site.

Conclusions Progressive changes in land-use, involving loss of rough grassland and a switch from dairy to sheep farming, may have contributed to the declines at one of the sites. However, there was no obvious change in land-use or habitat loss at the other site where population declines began 5 to 10 years earlier. Such declines have probably occurred widely in moorland-edge areas during the last 30 years and multiple factors may be responsible.     

Correcting observer effect bias in estimates of nesting success of a coastal bird,the White-fronted Plover Charadrius marginatus

Capsule A recently developed observer-effects model gives better estimates than the survival model.

Aims To compare the performance of the traditional survival model with that of an observer-effects model in estimating nesting success.

Methods We used survival data from 654 nests in a covariate-dependent extension of a maximum-likelihood estimator model to simultaneously estimate daily survival rate and observer effect on nesting success in four different sectors of a study site. Standard likelihood-ratio tests and Akaike's information criterion differences were used to compare model performances.

Results A significant (negative) observer effect was detected in one of four sectors of the study area, and was probably attributable to small mammal predators. Despite significantly higher predation risk during the laying period, there was a significant positive observer effect during the laying period, contrasting with a weak negative effect during the incubation period, suggesting that an observer's tracks around unattended nests reduced predation risk. Likelihood-ratio tests indicated a significantly better fit using the observer effects model versus the Mayfield survival model in four of six scenarios.

Conclusion The observer-effects model accounts for bias in estimates of nest survival rates, and is preferred over the survival model because the inclusion of observer effect as a variable does not over-parameterize the model.     

Dramatic changes in the return date of Guillemots Uria aalge to colonies in Shetland, 1962–2005

Capsule Changes in return date coincided with marked changes in population size that probably resulted in fluctuating competition for nest-sites.

Aims To document the changes in return dates over a 44-year period and to identify the factors associated with these changes.

Methods We compared changes in return date at Shetland colonies with those for the Isle of May, southeast Scotland, and with the available information on population size, the abundance of some fish species eaten by Common Guillemots and large-scale changes in the oceanography and climate of the eastern Atlantic as reflected by the winter index of the North Atlantic Oscillation (NAO).

Results Common Guillemots normally return to colonies in Shetland in late winter. However, during the 1960s return dates became gradually earlier with birds present from early October. Autumn return remained the norm for about ten years after which return dates gradually reverted back to late winter. In contrast, Common Guillemots on the Isle of May, 400 km south of Shetland, showed no marked shift, returning in October each year. There was a strong negative correlation between date of return of Shetland birds and population size, whereas on the Isle of May birds came back earlier when there was a large positive winter NAO index. There was no convincing evidence that changes in wintering areas or fish abundance influenced when birds returned to the colonies, although the fish data may not have been collected on the correct spatial scale.

Conclusion Competition for high quality nest-sites is the most likely reason for Common Guillemots returning to the colonies during the autumn and winter.     

The phenology of spring bird migration to north Norway

Capsule There was no evidence of a long-term trend in arrival dates of spring migrants over the last 20 years in north Norway.

Aims To investigate the effect of climate on the timing of spring arrival of many species at their northern limit of breeding distribution and to seek evidence of any long-term trend.

Methods Observations of spring arrivals of 71 species into Troms, north Norway (69–70°N) between 1970 and 2000 by members of the local branch of the Norwegian Ornithological Society were analysed and related to available weather parameters.

Results The first migrants arrive in mid-March when air temperatures are still below 0°C and c. 1 m of snow is on the ground, with the main influx in late April and throughout May. By then much of the snow has melted and temperatures are c. 5°C. There was no evidence of a long-term trend in the median dates of arrival across 31 species in Troms between 1980 and 2000. However among 14 species for which detailed data exist in a limited area around Tromsø, the Golden Plover Pluvialis apricaria showed a significant trend towards an earlier arrival and the Willow Warbler Phylloscopus trochilus showed the opposite. Spring migration tended to be advanced during warm springs, and seven of the above subsets of 14 species showed significant negative correlations between their arrival dates and temperature. One showed a positive correlation.

Conclusion The data collected to date are a good baseline for future studies of the effects of climate change on migration phenology.