Roosting and associated feeding behaviour of turnstones Arenaria Interpres and purple sandpipers Calidris maritima in north-east England

Both individual Turnstones and Purple Sandpipers were largely site-faithful during winter; after the breeding season, however, fewer surviving Purple Sandpipers than Turnstones returned to the study area. Both species were sedentary on small low water home ranges and were faithful to a small number of roost and high water sites. Numbers of Turnstones and Purple Sandpipers flying to the main high water roost, Hartlepool West Harbour, were greatest on spring high tides, but were reduced m high winds. Numbers at other high water sites at nearby Hartlepool Headland were greatest on neap tides. Maximum Purple Sandpiper numbers at West Harbour showed a steady decline over the period from 1986/87 to 1993/94; maximum numbers of Turnstones dropped sharply in 1993/94 after redevelopment of the harbour m 1991/92. Overall disturbance rates to roosting shorebirds at West Harbour, and those from boats and man, increased over the study period and were probably responsible for the decline in Turnstone numbers and those of two other species. An artificial island, built m 1991/92, is now the main roost site for all species. Intraspecific aggression on the feeding grounds was primarily a result of encounters over food; infringements of individual distance were relatively infrequent Dominance hierarchies on low water feeding grounds were stable for both species; adult Turnstones dominated first-winter bkds; Purple Sandpiper dominance was positively correlated with size. Survival was not related to dominance for either species. Both species were segregated at the West Harbour roost into groups from different low water feeding areas; Purple Sandpipers also into groups of different (bill-length) size class. Aggression at the roost resulted from encounters over roosting sites or infringements of individual distance. As wind speed increased, encounters over roosting sites became more frequent and intensity of aggression increased. Dominance hierarchies at the roost were stable for both species; individual roosting dominance was positively correlated, though not always significantly so, to low water feeding dominance. Adult Turnstones dominated first-winter birds; Purple Sandpiper dominance was positively correlated with size. Roosting flocks were structured in accordance with dominance relationships: adults and dominants occupying denser, middle positions and first-winters and subordinates less dense, peripheral sites. Individuals (of both species) that were subordinate at the West Harbour roost frequented it less often than dominants (at least in some seasons), probably because they could not obtain good roosting positions there. Other sites allowed these birds to feed over high water. Turnstones and Purple Sandpipers associated together frequently at the West Harbour roost in comparison to other species. There was no evidence that either species roosted with the other in order to exchange information concerning food resources or to save energy through the roost's microclimate. Both species shared vigilance with each other and probably roosted together m order to decrease the risk of being taken by a predator

Individual, sexual and temporal variation in the winter home range sizes of GPS-tagged Eurasian Curlews Numenius arquata

Capsule: Eurasian Curlews Numenius arquata were faithful to foraging and roosting areas on their coastal wintering grounds, including a habitat creation site. Home range sizes were greater at night than during the day, and showed high inter-individual variability which was not related to sex. Aims: To examine factors affecting variation in the winter home range size of the largest European wader species: the near-threatened Eurasian Curlew Numenius arquata. Methods: We examined individual, sexual and temporal (day/night, seasonal and annual) variation in the size of the home ranges of 18 GPS tagged Curlews captured at two sites on the Humber Estuary, UK. Results: Home ranges were small (mean ± SD = 555.5 ± 557.9 ha) and varied slightly in size through the non-breeding season (September–March). We found some annual differences in home range size, and there was some evidence that home range size was greater at night compared to daytime. There was strong inter-individual variation in home range size, which was not related to the species’ sexual size dimorphism and thus potential differences in resource use. Conclusions: Our results highlight that wintering Curlews on the Humber Estuary maintain small home ranges which vary strongly between individuals. Knowledge of the home range size of wintering waders is vital to inform management responses to the potential impacts of environmental changes such as sea-level rise and improving the efficacy of compensatory habitats

Habitat selection and specialisation of herring gulls during the non-breeding season

Understanding both the distribution and habitat use of populations through the annual cycle is vital to understanding how vulnerable species are to environmental change. However, distributions and habitat use can vary among individuals and populations, particularly in generalist species, with variation depending on external environmental factors, such as resource availability. Comprehensive information across multiple populations is important to guide spatial planning of protected areas and is increasingly available for breeding individuals, but it is still lacking for many species, particularly seabirds, during the non-breeding season, especially those with declining populations. We investigated within-species variation in migratory strategies, non-breeding habitat selection and habitat and spatial specialisation in a declining, opportunistic, generalist seabird, the European herring gull Larus argentatus, from multiple breeding colonies across northwest England and southwest Scotland using global positioning system (GPS) tracking during the non-breeding season of 2014/15. Although several individuals stayed within the area of the breeding colony, the majority of individuals migrated in a southerly direction and spent half of the annual cycle (on average 53%) away from the breeding area and kept moving through the non-breeding period. During non-breeding, herring gulls selected mainly marine intertidal, but also a range of anthropogenic terrestrial habitats. However, habitat selection differed between geographical regions, within a geographical region and among individuals. There was a generalist use of non-breeding habitats at the population level, but some habitat specialisation at the individual level that was repeatable through the non-breeding period despite individuals showing low spatial specialisation. The results highlight the importance of intertidal habitat and a mix of alternative foraging habitats in the wintering areas of herring gulls. The results also highlight that habitat selection in an opportunistic generalist can vary even between nearby regions and that appropriate conservation management plans may need to be tailored to regional differences in specific non-breeding areas

Long-Term Changes in the Abundance of Benthic Foraging Birds in a Restored Wetland

Estuaries have historically been subject to considerable habitat loss, and continue to be subjected to such in areas where the natural landward migration of intertidal habitats is constrained by hard coastal defences. Thus, in estuaries where direct (e.g., port development) or indirect (e.g., sea level rise) processes are predicted to threaten intertidal habitats and associated waterbird species, there is a regulatory requirement to produce compensatory intertidal habitats. Managed realignment (MR) is a shoreline management practise that is undertaken to build sustainable coastal defences and create intertidal habitats in estuaries. This nature-based solution brings multiple benefits in the form of carbon storage, increased resilience to flooding, and, potentially, the formation of new habitats, which is the topic of this study. A 75-ha site at the Paull Holme Strays (Humber Estuary, United Kingdom) was monitored over a 10-year period following MR to examine the change in the abundance of waterbirds in the chosen site in response to the physical processes occurring there. Using digital terrain models (DTMs) collected via light detection and ranging (LiDAR), we examined how four compensatory target species responded to changes in elevation after the creation of the site. It was shown that the very rapid accretion of estuarine sediment occurred in the first decade of the new re-created intertidal, which, over time, led to changes in the numbers of benthic foraging birds supported. Furthermore, elevation change was also driven by this sediment accretion, the rate of which depended on the initial bed elevation of the sectors within the site. Ten years after the recreation of the habitat, the spatial heterogeneity in the bed elevation remained high; however, the sectors with the lowest elevations accreted the most over the 10-year period. The foraging number of the four waterbird species that colonised the MR site significantly declined above a certain elevation, with this effect being most pronounced for the Eurasian curlew (Numenius arquata). The number of common shelducks (Tadorna tadorna), dunlins (Calidris alpina), and common redshanks (Tringa totanus) declined significantly after initial peaks 5–7 years after the creation of the site, reflecting the ongoing elevation changes. Thus, this study highlighted the need for long-term studies to understand how species respond to large-scale habitat construction. It can also aid in predicting the suitability of an MR site for waterbirds in the medium and long term

Urban Breeding Gull Surveys: a Survey Design Simulation

No abstract available

GPS tracking reveals landfill closures induce higher foraging effort and habitat switching in gulls

Abstract Background Landfills are a major subsidy for some animals, with implications for their life history and demography. Gulls feed extensively on food from landfills and closures are expected to have ecological consequences, but how this influences movement ecology is virtually unknown. Methods We used GPS-tracking to quantify foraging behaviour and habitat choice of lesser black-backed gulls (Larus fuscus) breeding at two colonies before and after closure of two nearby landfills. Results Following closure, gulls from both colonies travelled further and for longer to forage. Gulls also changed habitat selection, although this differed by colony - birds from one colony shifted to agricultural habitats, while at the other, increased their use of urban areas. These behavioural responses had no effect on adult body condition but hint at potential direct effects of higher foraging costs and indirect impacts by shifting to new habitats. Conclusions Our results demonstrate how landfill availability influences gull foraging movements and habitat selection. We also emphasize the value of biologging to detect rapid behavioural responses in contrast to more conventional demographic approaches, which is especially important for animals that spend the majority of their lives away from direct observation

Gridded tracking data for estimation of sensitivity and vulnerability of Lesser Black-backed Gulls (Larus fuscus) to wind farm collision risk

Metrics derived from GPS telemetry of individual Lesser Black-backed Gulls (Larus fuscus) throughout the year at three UK breeding colonies. Data are summarised per grid square across the spatial range of birds. Metrics in the file include the mean time spent and mean speed of travel per square for all movements, in flight activity, and for movements within the collision risk window (CRW) - see associated readme file. Mean distances travelled per square in the CRW are then calculated for each square and are used to estimate spatio-temporal sensitivity

Lesser Black-backed Gull flight height data

This file was created with R. 'Bird.id', 'date_time', 'latitude', 'longitude', 'altitude', 'positiondop' and 'speed' were collected by GPS tags. 'Positiondop' is dilution of precision. 'Altitude' is measured in m and 'speed' in km/h. 'Marine' denotes observations over land (0) or sea (1), derived from overlaying the GPS measurements on a map in ArcGIS. 'Coastal' donates observations at sea but within 200 m of the coast (1) or further from the coast (0), again derived in ArcGIS. Tidal data ('tidal.state' in m) were from the British Oceanographic Data Centre (https://www.bodc.ac.uk/data/online_delivery/ntslf/), using tide gauge from Harwich. Surface elevation ('land_height' in m) was obtained from the Shuttle Radar Topography Mission 90 m digital elevation data (http://srtm.csi.cgiar.org/http://srtm.csi.cgiar.org/), aggregated at the 1 km square level. Sunrise and sunset information was obtained using the NOAA Sunrise/Sunset Calculator (http://www.srrb.noaa.gov/highlights/sunrise/sunrise.html)

Great Skua flight height data

This file was created with R. 'Bird.id', 'date_time', 'latitude', 'longitude', 'altitude', 'positiondop' and 'speed' were collected by GPS tags. 'Positiondop' is dilution of precision. 'Altitude' is measured in m and 'speed' in km/h. 'Marine' denotes observations over land (0) or sea (1), derived from overlaying the GPS measurements on a map in ArcGIS. Tidal data ('tidal.state' in m) were from the British Oceanographic Data Centre (https://www.bodc.ac.uk/data/online_delivery/ntslf/), using tide gauge from Lerwick and Wick. Surface elevation ('land_height' in m) was obtained from the Shuttle Radar Topography Mission 90 m digital elevation data (http://srtm.csi.cgiar.org/http://srtm.csi.cgiar.org/), aggregated at the 1 km square level. Sunrise and sunset information was obtained using the NOAA Sunrise/Sunset Calculator (http://www.srrb.noaa.gov/highlights/sunrise/sunrise.html)