Eidechsen on the news!

Jonas Martiny has pubblished on Mallorcan Magazine an extensive article on the Balearic lizards. It includes information on the natural history of Podarcis pityusensis and Podarcis lilfordi, and an interesting section on the early studies, carried out in the middle of the last century, on lizard taxonomy and evolution. It also refers to the work by GEDA on photo-recognition and on the study of life-history tactics of the Balearic Wall lizard.

Shearwater "6080638" from nest 670

Sad news. Via the ZEPAMAR project (SEO-Birdlife) a fisherman has reported several Scopoli's shearwaters, Calonectris diomedea, accidentally killed in longlines. Among them, a 26-year-old male, ring 6080638, that bred in the colony at Dragonera Natural Park, off the coast of Mallorca. The Animal Demography and Ecology Group (GEDA-IMEDEA) monitored the colony since 2001, gathering the phenology and breeding success of more than 300 breeding shearwaters, among them bird 6080638, from nest 670. The experienced male carried a geolocator for few years reporting precious information on the wintering ground, the feeding strategy and his breeding phenology. He was born in the same colony in 1993 and began to breed at Dragonera Natural Park in 2002. Each year he occupied nest 670 taking care of the nest, sharing the incubation of the egg with his partner and rising his chick during the summer. He was able to breed in 2012 when many shearwaters died due to the harsh winter conditions. He died in March 2020 caught on a longline. Scopoli’s shearwaters are very sensitive to accidental fishing, probably the main threat for the species. Long-term ringing schemes, as the one conducted by the GEDA, helped to obtain an estimate of the mortality due to bycatch. At this colony, between 7 and 10% of the population is estimated to die by accidental catches. A figure similar to the one of other causes of mortality, most of them, related directly or indirectly to human activities. Demographic studies suggest that the colony is going slowly toward the extinction (here and here). 

Photo: VictorParis

At present the colony acts as a population sink and the number of breeding shearwaters are maintained by immigration of individuals from other colonies (details here). Bird 6080638 has contributed for many years to this knowledge, fundamental to understand the functioning of the colony and to identify mitigation actions. Now he has joint the mortality database. Thanks to the fisherman that has reported the accidental catch, we know that 6080638 was caught in an area near the colony. An area thought to have a low risk of bycatch based on the data collected on the Balearic fishing fleet. But the mortality accidentally caused by artisanal fishing is more difficult to predict and its magnitude is still unknown. It is a large-scale problem becasue bycatches occur in both artisanal and industrial fisheries in the breeding as well as the wintering areas and they represent a serious threat also for other shearwaters, such as the Balearic shearwater, Puffinus mauretanicus.

This entry is a small tribute to 6080638 from nest 670. We will miss him. He helped us to refine our knowledge on the problem of bycatch and to move with the contribution of all, scientists, conservation institutions and fishermen toward solutions.

GEDA at 11FBalears: International Day of Women and Girls in Science

 

An interview to several scientists from the IMEDEA here
 

Gulls in Ibiza! If you are resident on the island, join the investigation!

Yellow-legged gulls are perceived by some as "bad" and "dangerous" and considered a nuisance. For others, the species is simply fulfilling its role of predator and generalist forager as do other species, such as cats. The GEDA has launched an investigation in Ibiza to assess the perception of gulls by the general public and help to mitigate potential human-wildlife conflicts.

If you are resident in Ibiza, you can join the investigation here at

http://viis.abdn.ac.uk/snapwebhost/s.asp?k=159895186855

For more information on the enquire, read the new press release here

Prospecting..?

After a summer in the Alicante region, the Yellow-legged gull "G_1394" came back to its colony the 24th of January. Few days later it returned to Alicante. Is this a prospection or the gull found something wrong with the colony and move to Alicante to breed ?  The prospecting behaviour is still poorly studied but increasing evidence suggests it is more common than previously thought. Stay tuned to know what "G_1394" will do in early spring.

New Publication on Red Kite conservation!

Sergio, F, Tavecchia, G., Blas, J., Taferna, A., Hiraldo, F.  2021. Demographic modeling to fine‐tune conservation targets: importance of pre‐adults for the decline of an endangered raptor. Ecological Applications, https://doi.org/10.1002/eap.2266

Summary: Large, long‐lived species with slow life histories and protracted pre‐breeding stages are particularly susceptible to declines and extinction, often for unknown causes. Here, we show how demographic modeling of a medium‐sized raptor, the Red Kite Milvus milvus, can aid to refocus conservation research and attention on the most likely mechanisms driving its decline. Red Kites’ survival and reproduction increased through three sequential stages for 1–2, 3–6, and 7–30 yr of age, mainly corresponding to individuals that are dispersing, attempting to gain a territory, and breeding. As typical of long‐lived species, elasticities were highest for adult (≥7 yr old) survival, but this was high, with little scope for improvement. Instead, the declines were driven by an extremely low survival of pre‐adults in their first years of life, which weakened the whole demographic system by nullifying the offspring contribution of adults and curtailing their replacement by recruits. For example, 27 pairs were necessary to generate a single prime age adult. Simulation of management scenarios suggested that the decline could be halted most parsimoniously by increasing pre‐adult survival to the mean levels recorded for other areas, while only the synergistic, simultaneous improvement of breeding success, adult and pre‐adult survival could generate a recovery. We propose three actions to attain such goals through selective supplementary feeding of both breeding and non‐breeding individuals, and through mortality improvement by GPS remote‐sensing devices employed as surveillance monitoring tools. Our results show how improving demographic models by using real, local vital rates rather than “best guess” vital rates can dramatically improve model realism by refocusing attention on the actual stages and mortality causes in need of manipulation, thus building precious time and resources for conservation management. These results also highlight the frequent key role of pre‐adult survival for the management of long‐lived species, coherent with the idea of demographic systems as integrated chains only as strong as their weakest link.

 

 

 

New Publication on Urban Ecology!

Luna, Á., Lois, N.A., Rodríguez-Martinez, S., Palma, A., Sanz-Aguilar, A., Tella, J. L. Carrete, M.. 2021 Urban life promotes delayed dispersal and family living in a non-social bird species. Scientific Report 11, 107 (2021). https://doi.org/10.1038/s41598-020-80344-8

Abstract. In some vertebrate species, family units are typically formed when sexually mature individuals delay dispersal and independent breeding to remain as subordinates in a breeding group. This behaviour has been intensively studied in gregarious species but has also been described in non-social species where ecological and evolutionary drivers are less known.

Photo: N. Rebolo

Here, we explore factors that favour delayed dispersal and family living and potential benefits associated with this strategy in a non-social, monogamous species (the burrowing owl, Athene cunicularia) occupying urban and rural habitats. Our results show that family units arise when first-year individuals, mainly males, delay their dispersal to stay in their natal nests with their parents. This delayed dispersal, while still uncommon, was more prevalent in urban (7%) than in rural (3%) habitats, and in areas with high conspecific density and productivity. Birds delaying dispersal contributed to the genetic pool of the offspring in 25% of the families analysed, but did not increase the productivity of the nests where they remained. However, their presence was related to an improvement in the body condition of chicks, which was ultimately linked to a slightly positive effect in offspring future survival probabilities. Finally, delayed dispersers were recruited as breeders in high-quality urban territories and closer to their natal nests than individuals dispersing during their first year of life. Thus, our results suggest that delaying dispersal may be mainly related to opportunities to inheriting a good quality territory, especially for males. Our study contributes to understanding the role played by habitat quality in promoting delayed dispersal and family living, not only in social but also non-social species, highlighting its impact in the ecology and evolution of animal populations.

Fieldwork at the Cabrera National Park

GEDA has monitored lizard density in a small area of the Cabrera National Park. The campaign is part of the extension of the monitoring program in the southern islands of Mallorca, financed by the Government of Balearic Islands (code: PRD2018/25). 

A big 'thank' to the Park who helped with the logistic.