Results from the first GPS tracking of roof-nesting Herring GullsLarus argentatusin the UK

Abstract

Recent developments in GPS tracking technology are allowing the movements of bird species to be followed in ever greater detail. Seabird research is benefiting greatly due to the challenges of tracking species that often roam widely out at sea. Amongst the gulls, one of the pressing issues is to understand the ecology of the relatively recent urban colonists and how they differ from their counterparts in traditional rural colonies. Here, we present what we believe are the first GPS results from roof-nesting gulls. Four adult Herring Gulls (two males, two females) were fitted with GPS tags in May 2014 in the seaside town of St Ives, Cornwall (breeding colony ca. 250 pairs) and tracked for ca 100 days through the 2014 breeding season. We estimated the home ranges of the four individuals and how their movement behaviour varied through the 24h period and across the breeding season. The results highlight how variable movement behaviour was among individuals: whilst one bird roamed widely (90% range estimate = 560km 2 ), heading >50km offshore and often active at night or roosting at sea, two birds had small ranges (<10km 2 ), always attended the colony at night and rarely headed more than a few hundred metres offshore, with the fourth displaying intermediate behaviour. All of the birds regularly utilised a few key sites within the agricultural landscape south of St Ives. Whilst this study was too small to allow general conclusions about urban Herring Gulls to be drawn, it reinforces how variable individual behaviour can be in the large gulls and will be particularly interesting when applied to a larger sample of birds, especially in big urban gull colonies further upcountry.

Intercolony variations in movement patterns and foraging behaviors among herring gulls (Larus argentatus) breeding in the eastern Wadden Sea

“…Within‐colony variation in individual movement patterns was recently demonstrated for roof‐nesting herring gulls, based on GPS data (Rock et al, 2016). A multi‐colony approach, based on pellets and stable isotope data of chicks, showed that the breeding success of herring gulls in Scotland depended on the foraging habitat.…”

Shifting individual habitat specialization of a successful predator living in anthropogenic landscapes

“…They efficiently adapt to exploiting a wide suite of novel resources that provide direct biotic and abiotic benefits, including food, shelter and refuge from predation (Ramírez et al 2012, Alonso et al 2015, Osterback et al 2015. These winning seabirds are often perceived as pests because of their impacts on urban areas, water reservoirs and threatened species (Vidal et al 1998, Skórka et al 2014, Rock et al 2016. As a consequence, abundant research has been conducted on these opportunistic predators, mainly focused on their population dynamics, feeding ecology, pollution levels and pathogen load (e.g.…”

Uso del espacio por adultos de gaviota patiamarilla Larus michahellis Naumann, 1840 durante el periodo reproductor: resultados preliminares en relación al uso de vertederos.

“…1) abarca, en términos globales, (1) la franja de costa desde la colonia de Ulía hasta el punto de alimentación en el vertedero de Zaluaga en Senpere, (2) otra franja de territorio a lo largo de un eje que une la colonia con el vertedero de Sasieta en Beasain (con una nube de puntos densa en zonas de prados y paisaje de campiña en la zona baja de la cuenca del Urumea así como en la cuenca del río Oria, particularmente en el Asteasu), (3) un área marina de unos 1500 km 2 frente a la colonia. En promedio, la superficie (polí-gono mínimo convexo) (Bosch et al, 2009;Rock et al, 2016) abarcada por cada ejemplar fue de 911,34 km 2 (SE = 425,74 km 2 ; rango: 307,75-2158,10 km 2 ; Tabla 1; Fig. 2).…”

“…Nuestros resultados son consistentes con otros estudios sobre ecología espacial en gaviotas (Bouten et al, 2013;Tyson et al, 2015;Rock et al, 2016). Los resultados mostrados en este Tabla 2.-Porcentaje de localizaciones nocturnas y diurnas según hábitat, durante el periodo de reproducción (meses de junio y julio), de 4 ejemplares adultos de gaviota patiamarilla marcados en la colonia de Ulía (Donostia).…”

“…Debido al carácter preliminar y descriptivo de este artículo, se decidió no desarrollar análisis estadísticos más complejos que, tal vez, pudieran permitir esclarecer, al menos en un porcentaje de las localizaciones, si eran posiciones en el suelo o en vuelo. Estudios similares también incluyen todas las localizaciones sin distinguir si éstas eran en vuelo o posadas (Rock et al, 2016 …”