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download-button-0409-lg1st Common Swift Seminars, Berlin 2010 - Summaries


ABSTRACTS


Status and trends in Spain

Based on the data from the last Atlas of Breeding Birds in Spain (2004), the minimum population of Common Swifts is considered around 620.000 breeding pairs (no data from 18% of the territory). Previously in 1997 were estimated in 450.000-600.000 pairs. On the other hand, the Atlas of Breeding Birds in Catalonia (2002), a region North-East Spain which represents the 6% of the Spanish territory exposes a breeding population between 203.000-288.000 pairs. When comparing both censuses, we observe quite an important inconsistency, possibly due to the difficulty to obtain an accurate census of this species. How such small territory contains one third of the Spanish breeding population? In 1988 Bernis, a Swift researcher, estimated the breeding population in Spain in around the million, and later on even estimated the population in a few millions! How that estimation was changed? Based in new census techniques? In addition, the database from the long-term monitoring scheme on common breeding birds in Spain (SACRE), from the Spanish Ornithological Association (SEO), estimated the average population sizes of 95 species from 2004 to 2006. They published an estimated for the Common swifts that seems hard to believe, 32.750.000, yes that’s 32 millions (the study refers to a general population, not breeding birds). I personally have addressed to SEO about the reliability of this data, which to me (and some other professional ornithologist) is absolutely inaccurate for this species. All this mixture of data exposes an important concern; there is no accurate data to expose an accurate population thus describe the trend of the species in Spain.

 

Enric Fusté BSc (Hons) Msc MSB


Current research on diets

Until 2008, Torreferrusa Wildlife Rehabilitation Centre (CRFST) in Barcelona was using a diet based on rat mince to hand-rear common swifts (Apus apus) orphans. In order to assess the performance of this diet, growth rates and body weight of hand-reared common swifts at release were compared to those of wild parent-raised. The results showed significant  Differences in final weight, being remarkably lower for hand-reared birds on the rat mince diet (rat mince diet 32.8g SD ± 2.7 vs. Wild 42.6 SD ± 3.9g). In 2009 CRFST extended the diet study by including three additional diets: one based on the FoNS 08 © formula (kibble diet), where the main ingredient is a high protein-low carbohydrate cat food (Orijin ®); one based on crickets (90% Acheta domesticus, 10% Galleria mellonella) and a third one using exclusively mealworm larvae (Tenebrio molitor). Insect diets were particularly supplemented with vitamins and minerals. The mealworm diet is somehow controversial; however it is used successfully in hand-rearing Chimney swift (Chaetura pelagica) in the US. Histopathological evaluations of tissues conducted in three birds fed for more than 20 days on mealworm gave no evidence of illnesses of nutritional origin or damage in internal organs. The final weights results in both insect diets groups were highly satisfactory, with values close to those on the wild (Cricket 40.1g SD ± 4.2 – Mealworm 40.3g SD ± 3.1). The results for the kibble diet were not as optimal as expected according to the literature reviews as they had low final weights (32.5g SD ± 3.7). Survival results on the two insect diets discard any sacrifice protocol based on clinical condition at admission. The results expose the need to implement changes in the diet protocols when using those non-based insect diets. Under the circumstances, the expensive cricket diet cannot be provided for economical reasons. The results encourage and support the possibility to use the less expensive mealworm diet with  Proven success as a base diet for all admissions on the oncoming season in Torreferrussa, analyzing the outcome results with care.

 

Enric Fusté BSc (Hons) Msc MSB


Diet and Cost Balance: A way forward?

Nestlings in captivity should be fed the same food the parents would have fed them in the wild. Diets for insectivore birds represent a real challenge. Clearly, the desirable diet would be composed of diverse insect species. However, this cannot be feasible in many wildlife rehabilitation centres where large numbers of chicks are hand-reared. An insect diet mainly based on crickets (Acheta domesticus) is used in some specialized rehabilitation centres in Europe to hand-rear swifts. This diet is most favourable in terms of recovery, reaching optimal fledging weights and feather condition. Nonetheless, crickets are expensive items and they cannot be provided for economical reasons. The results of a diet research conducted in Torreferrussa Wildlife Rehabilitation Centre encourage and support the possibility to use the less expensive mealworm larvae (Tenebrio molitor) diet as a base for all the admissions on the Apus species. Commercially produced insects can be deficient in some nutritional components, being mealworm larvae particularly deficient in some vitamins and minerals.The mealworm diet formula has to be followed strictly to cover those nutritional deficiencies. Other strategies can also be conducted to supplement the diet with different insect species at low cost. Examples of in-house production of some species with easy breeding biology are: silk worm (Bombyx mori); wax moth larvae (Galleria mellonella); Dubia cockroach (Blaptica dubia); drones (Apis mellifera) obtained from regional bee-keepers and finally wild insects captured using pheromones traps (mainly coleopteran). The mealworm diet will be used in all expected admissions (790 on year 2009), providing an excellent outcome and hopefully settling this diet as definitive. The desired objectives are to obtain release weight close to 40g and to increase the survival rate.

 

Enric Fusté BSc (Hons) Msc MSB