José A. Gil-Delgado

Patterns of nestling provisioning by a single-prey loader bird, Great Tit Parus major

Capsule Nestling provisioning rates depend on nestling age and number, and on time of season, but not on time of day. Aims To determine patterns of nestling provisioning, the effort made by the parents, and the factors which affect them. Methods Mechanical counters to determine food provisioning patterns in 229 Great Tit Parus major nests over 4 years. Results Feeding frequency per chick showed a linear increase with nestling age and total feeding frequency stabilized towards the end of the nestling period. The number of visits per nest increased linearly, while those per nestling decreased linearly with brood‐size. Feeding rates per nest declined throughout the breeding season parallel to the seasonal brood‐size decline; feeding frequencies per nestling did not vary seasonally. Adult effort was almost constant throughout the day, independently of variations in brood‐size, ambient temperature and date. Conclusion Previous studies of nestling provisioning patterns were either contradictory or poorly supported by low sample sizes. The present study involved a much larger sample and clarifies nestling provisioning patterns and the factors with which they are associated.

Laying date and clutch size of Great Tits(Parus major) in the Mediterranean region: a comparison of four habitat types

Laying data and clutch size of Great Tits were studied in four different habitats in eastern Spain: two holm oak(Quercus ilex) forests, at 500 and 900–950 m a.s.l., a zeen oak(Quercus faginea) forest, at 900–1100 m a.s.l., a pine(Pinus sylvestris) forest, at 1000–1050 m a.s.l., and orange(Citrus aurantium) plantations, at 30 m a.s.l. All sites were placed at about the same latitude (39–41°N), and all were studied during the same years (1992–95). Our results show that (1) laying date did not differ between the natural habitats at the same altitude (range of the means of yearly means 4–8 May); (2) within the same habitat type (holm oak forest) laying date was earlier at low altitude (30 Aprilvs. 8 May); (3) laying date was earlier in the orange plantations (21 April) than in natural habitats; (4) among natural habitats at the same altitude, clutch size decreased from zeen oak (mean of yearly means 7.3 eggs) to holm oak (7.0 eggs) to pine forests (6.4 eggs), though only the difference between zeen oak and pine forests was significant; (5) within the same habitat type (holm oak forest), the clutch size tended to be larger at high altitude (7.0vs. 5.9 eggs); and (6) clutch size in orange plantations (7.7 eggs) did not differ significantly from that of the zeen oak forest, but was larger than in the holm oak and pine forests. We discuss the effect of the habitat type on laying date and clutch size of Great Tits. Legedatum und Gelegegröße der Kohlmeise wurden in vier unterschiedlichen Biotopen in Ostspanien untersucht: zwei Steineichenwälder(Quercus ilex) in 500 m und 900–950 mNN, ein Bergeichenwald(Quercus faginea) in 900–1100 mNN, ein Kiefernwald(Pinus sylvestris) in 1000–1050 mNN und eine Orangenpflanzung(Citrus aurantium) in 30 mNN. Alle fünf Gebiete lagen auf etwa demselben Breitengrad (39–41°N) und wurden 1992–1995 parallel untersucht. (1) Auf gleicher Meereshöhe unterscheidet sich der Legebeginn nicht zwischen den verschiedenen Waldbiotopen (im Mittel 4.–8. Mai). (2) Innerhalb desselben Biotoptyps (Steineichenwald) war der Legebeginn auf niedrigerer Meereshöhe früher als in höheren Lagen (30. April vs. 8. Mai). (3) Im Orangenhain wurde früher mit der Eiablage begonnen (21. April) als in den Waldbiotopen. (4) Auf gleicher Meereshöhe nahm die Gelegegröße vom Bergeichenwald (Mittelwert 7.3 Eier) über die Steineichenwälder (7,0 Eier) zum Kiefernwald hin ab (6.4 Eier), jedoch ist nur der Unterschied zwischen Bergeichenwald und Kiefernwald signifikant. (5) Innerhalb der Steineichenwälder besteht die Tendenz zu größerer Gelegegröße in den höheren Lagen (7.0 vs. 5.9 Eier). (6) Im Orangenhain war die Gelegegröße mit durchschnittlich 7.7 Eier ähnlich der im Bergeichenwald, aber größer als in den Steineichen- und Kiefernwälder.

Population changes and breeding ecology of the Cirl Bunting Emberiza cirlus in eastern Spain

The number of Cirl Bunting Emberiza cirlus breeding pairs was recorded from 1976 to 1993 in orange plantations in eastern Spain, and some aspects of the breeding ecology of this species were studied from 1989 to 1993. Breeding densities varied from 0.6 to 10.1 pairs per 10 ha, being highest during the last 5 years. Breeding density each year was positively correlated with rainfall during the previous December–March period, but not to winter temperatures. The mean laying date was 17 April, and between-year variation was almost entirely determined (97% of the variation) by rainfall during December–March. The last clutches were laid by early July. Mean clutch size was 3.5 eggs. Clutch size increased during the first part of the season and then declined. About half of the nests were successful and half of the eggs laid produced fledglings. Predation accounted for most (35%) of the individual losses and was heavier early in the season. A logistic model was fitted to the weight data of the nestlings. Growth rat...

Breeding Ecology of the Blue Tit Parus caeruleus in Eastern Spain: A Comparison with Other Localities with Special Reference to Corsica

Aspects of the breeding ecology of the Blue Tit Parus caeruleus were studied in intermediate stages of succession in a holm oak forest at Monte Poblet (eastern Spain) from 1985 to 1991. In different years the density in two plots without nestboxes varied between 1.0 and 6.5 pairs per 10 ha. Nestbox introduction seems to have increased the density of breeding pairs. The mean laying date was earlier (6 vs. 13 May) in low altitude (500-750 m a.s.l.) plots than in a high altitude (900-1000 m a.s.l.) plot, but clutch size (6.9 vs. 6.5 eggs) was not significantly different (mean 6.6 eggs). No differences in mean laying dates were found between years. Significant differences in clutch size were found only between two years at the high altitude site. There was a slight, non-significant, seasonal decline in clutch size. No second clutches were laid. These results are discussed in the context of other Mediterranean studies with special focus on the differences and similarities between Corsican and mainland populations. It is shown that most of the characteristics of the Corsican population (i.e. density, habitat use, laying date, clutch size, number of broods per year) are shared by some populations on the mainland. On the other hand, some breeding traits of Blue Tit populations in southern France are closer to those of Central and North European populations than to the Iberian ones.

Invasion biology in non-free-living species: interactions between abiotic (climatic) and biotic (host availability) factors in geographical space in crayfish commensals (Ostracoda, Entocytheridae)

In invasion processes, both abiotic and biotic factors are considered essential, but the latter are usually disregarded when modeling the potential spread of exotic species. In the framework of set theory, interactions between biotic (B), abiotic (A), and movement-related (M) factors in the geographical space can be hypothesized with BAM diagrams and tested using ecological niche models (ENMs) to estimate A and B areas. The main aim of our survey was to evaluate the interactions between abiotic (climatic) and biotic (host availability) factors in geographical space for exotic symbionts (i.e., non-free-living species), using ENM techniques combined with a BAM framework and using exotic Entocytheridae (Ostracoda) found in Europe as model organisms. We carried out an extensive survey to evaluate the distribution of entocytherids hosted by crayfish in Europe by checking 94 European localities and 12 crayfish species. Both exotic entocytherid species found, Ankylocythere sinuosa and Uncinocythere occidentalis, were widely distributed in W Europe living on the exotic crayfish species Procambarus clarkii and Pacifastacus leniusculus, respectively. No entocytherids were observed in the remaining crayfish species. The suitable area for A. sinuosa was mainly restricted by its own limitations to minimum temperatures in W and N Europe and precipitation seasonality in circum-Mediterranean areas. Uncinocythere occidentalis was mostly restricted by host availability in circum-Mediterranean regions due to limitations of P. leniusculus to higher precipitation seasonality and maximum temperatures. The combination of ENMs with set theory allows studying the invasive biology of symbionts and provides clues about biogeographic barriers due to abiotic or biotic factors limiting the expansion of the symbiont in different regions of the invasive range. The relative importance of abiotic and biotic factors on geographical space can then be assessed and applied in conservation plans. This approach can also be implemented in other systems where the target species is closely interacting with other taxa.

Diet of the garden dormouse (Eliomys quercinus Linnaeus 1766) in orange groves: seasonal variation and use of available resources

Abstract The aim of this study was to describe the feeding habits of the garden dormouse Eliomys quercinus in orange groves of eastern Spain. The study area was an extensive orange grove near Sagunto (Valencia, Spain). This study combines two different non-invasive methods, the study of food store remains and the macroscopic analysis of feces. A total of 527 feces and the food remains of 172 food stores were recollected from nest boxes. Each feces was classified into five categories according to its characteristics: arthropods, gastropods, oranges, plants, and others. Throughout the year, the garden dormouse consumed all these types of food. The most consumed prey in summer and autumn were insects. However, in winter and spring orange fruit was the principal food type. Seasonal variation of orange, arthropods, gastropods, and plant matter consumption occurred. Among animal prey types, insects were the most consumed group and large-sized species were preferred. Vertebrate preys were found in food stores. The annual variation of the garden dormouse diet owing to the seasonal availability of resources in an agricultural environment revealed its feeding behavior plasticity.

Presence of plastic particles in waterbirds faeces collected in Spanish lakes

Plastic intake by marine vertebrates has been widely reported, but information about its presence in continental waterfowl is scarce. Here we analyzed faeces of waterbirds species (European coot, Fulica atra, mallard, Anas platyrhynchos and shelduck, Tadorna tadorna) for plastic debris in five wetlands in Central Spain. We collected 89 faeces of shelduck distributed in four lakes, 43.8% of them presented plastic remnants. Sixty percent of 10 faeces of European coot and 45% of 40 faeces of mallard contained plastic debris. Plastic debris found was of two types, threads and fragments, and were identified as remnants of plastic objects used in agricultural fields surrounding the lakes. Differences in prevalence of plastic in faeces, number of plastic pieces per excrement and size of the plastic pieces were not statistically significant between waterfowl species. Thus, our results suggest that plastic may also be frequently ingested by waterfowl in continental waters, at least in our study area. Future studies should address this potential problem for waterbird conservation in other wetlands to evaluate the real impact of this pollutant on waterbirds living in inland water.

Aspects of the breeding ecology of Rufous Bush Robins Cercotrichas galactotes in southeast Spain

The breeding ecology of Rufous Bush Robin Cercotrichas galactotes was studied over 4 years in southeast Spain. The vegetation of the study area was made up mainly of Olives, Almonds and small shrubs. The density of this species decreased from 0.36 pairs 10 ha-1 in 1980 to 0.7 pairs 10 ha-1 in 1984, a decrease similar to one observed in other parts of Spain. The breeding season lasted from late May or early June to late August. About two-thirds of the pairs laid 2 clutches. Mean clutch size was 3.6 eggs. The incubation period lasted about 13 days and nestlings left the nest after 10 days. Mortality was greater in first clutches, mainly because of predation, which did not occur in second clutches. Predation on nestlings was similar in first and second broods. Rufous Bush Robins were regularly parasitized by Cuckoos and we think that this species could be responsible for part of the predation on first clutches.

Populations of breeding birds in Byers Peninsula, Livingston Island, South Shetland Islands

Abstract Data about breeding populations of birds in the Antarctica are rare and fragmented. Thus, information about the status of the breeding populations of Antarctic birds is crucial given the current scenario of climate change, which is particularly acute in Antarctica. This paper presents new information about the populations of the Antarctic tern Sterna vittata, the kelp gull Larus dominicanus, the southern giant petrel Macronectes giganteus, the Antarctic skua Catharacta antarctica lonnbergi, the chinstrap penguin Pygoscelis antarctica and the gentoo penguin Pygoscelis papua on Byers Peninsula (Livingston Island, South Shetland Islands). We used line transects counts to estimate both densities and numbers of nests of the different species. We estimate that there are 398.96 birds km-2 of southern giant petrels (2793 individuals), 62.4 birds km-2 of Antarctic tern (3746 individuals) and 269.1 birds km-2 of kelp gull (1884 individuals). Furthermore, we found 15 nests of Antarctic skua in 25 km2, from which we can estimate that 60–91 birds must breed on Byers Peninsula. We also censused two colonies of gentoo penguins (3000 and 1200 pairs) and 50 pairs of chinstrap. Compared to previous estimates, gentoo penguins seem to have increased whereas chinstrap penguin have decreased. Finally, the populations of Antarctic tern, southern giant petrel and kelp gull have stabilized or slightly increased.

Winter reproduction of Eliomys quercinus (Rodentia) in the orange groves of Sagunto (Valencia, Spain) / La reproduction en hiver d' Eliomys quercinus (Rodentia) dans les orangeraies de Sagunto (Valence, Espagne)

Abstract The colonisation of orange groves in Eastern Spain by the garden dormouse Eliomys quercinus and their reproduction were studied. Litter sizes and times of birth of garden dormice were studied during the winter of 2003/2004 until the month of May 2004. The main study area was a plot covered by orange trees that has been monitored since 1975. Litters in nest boxes placed around the plot for birds, as well as a few litters in nests built in trees, were observed to obtain information on reproduction. The nests found in trees include some built in old bird nests, most of them belonging to the blackbird Turdus merula . We weighed the cubs to determine their month of birth and identified the population trend by counting the number of nests occupied simultaneously. Results show that there are births during the winter, that the number of cubs per nest ranged from 4 to 13, but 6 cubs was the mode. A total of 34 litters were found, with an average size of 5.76 cubs per litter. The litter of 13 cubs was excluded from analysis. Colonisation was suspected after a first specimen was observed in 1997 in the surroundings of the study area. Occupation by garden dormice of both natural nests and nest boxes subsequently increased from 1 to 27 between 1999 and 2004. We suggest that mild winter temperatures allowed the population increase and winter reproduction.