Short‐term effects on body condition and size of immunocompetent organs in the hooded crow

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Reproduction of the Crag Martin (Ptyonoprogne rupestris) in relation to weather and colony size

From 1994 to 1999, we investigated how climatic conditions influence the laying dates and number of fledged young of the Crag Martin Ptyonoprogne rupestris, a poorly studied colonial martin that, like other aerial feeding birds, is supposed to be highly dependent on weather conditions. Laying dates were concentrated in May and the first half of June. The mean annual laying date differed significantly among years; however, probably because of the small absolute difference between early and late years, there was no influence on the clutch size nor on the number of fledged young. Mean clutch size was 4.4 ± 0.9 eggs, the hatching rate was 80.2 percent, and the average number of fledged young was 3.1 ± 1.9. Temperature and rainfall in the days before laying and during the incubation period did not influence the breeding success, while in the chick rearing period there was a negative relationship between temperature and number of fledged young. It is supposed that high temperature can negatively influence breeding success through the drying up of small rivers where parents find food (mainly aquatic insects). In our study area the Crag Martins nested solitarily or in small colonies (mean 3.5 ± 1.9 nests). Colony size did not influence the laying date, the clutch size or the number of successfully fledged young

Studio delle condizioni fisiologiche e dell'ecologia di una popolazione di cornacchia grigia (Corvus corone cornix) nelle provincia di Alessandria

Dottorato di ricerca in scienze ambientali: acque interne e agrosistemi. 12. ciclo. A.a. 1998-99. Docente guida G. MalacarneConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Variation of body mass in Moorhens Gallinula chloropus wintering in a temperate area

The variation of mass during the winter season was studied in a Moorhen (Gallinula chloropu) population wintering in North Italy. The influence of 19 short-and long-term time and climatic parameters was evaluated both by single factor regressions and by multivariate analyses. Mass was related positively to the temperature of the days preceding capture and the 71 -year mean temperature, and negatively to the date, 71 -year temperature variability and photoperiod. Moorhens lost more mass after days with low temperatures and in periods with a high temperature variability. The composition of the body was evaluated by measurement of its electroconductivity with the Tobec system. This device gives an indication of the lean body mass, since the contribution of lipid tissue to conductivity is negligible. During the winter season the Moorhens had a small decrease of lean body mass index suggesting that the consistent weight decrease was due to lipid depletion. By experimentally exposing 36 Moorhens to different overnight temperatures we observed a higher decrease of body mass with lower night temperature. The weight changes in Moorhens did not follow the pattern of winter fattening found in many passerine species. Instead there was a noticeable seasonal decrease of mass (-30 %) linked to long-term climatic factors and an adjustment of body mass in relation to short-term temperature.La variation hivernale du poids corporel a été étudiée dans une population de Poules d’eau (Gallinula chloropus) hivernant dans le nord de l’Italie. L’influence de 19 paramètres temporels et climatiques, jouant tant sur le court que le long terme, a été évaluée à la fois par des régressions unifactorielles et des analyses multivariées. Des corrélations positives ont été observées entre le poids et la température des jours précédant la capture ainsi que la température moyenne sur 71 ans ; les corrélations furent négatives entre le poids et la date de capture, la variabilité de la température sur 71 ans et la photopériode. Les poules d’eau ont perdu le plus de poids après des jours à faible température et durant les périodes à forte variabilité thermique. La composition du corps fut mesurée par électro-conductivité à l’aide d’un système Tobec. Cet appareil donne une indication du poids maigre puisque la contribution des tissus lipidiques à la conductivité est négligeable. Durant l’hiver, les poules d’eau montrèrent une légère chute de l’indice de poids maigre suggérant que la baisse de poids observée était due à l’épuisement des lipides. En exposant expérimentalement 36 poules d’eau à des températures nocturnes différentes, nous observâmes des baisses de poids d’autant plus fortes que les températures nocturnes étaient plus faibles. Les changements de poids des poules d’eau n’ont pas suivi le patron d’engraissement hivernal observé chez beaucoup de passereaux. Au contraire, il y eut une baisse significative (-30 %) du poids en cette saison, liée à des facteurs climatiques jouant sur le long terme, ainsi qu’un ajustement du poids corporel aux variations à court terme de la température.Acquarone Camilla, Baiardi Renza, Cucco Marco, Malacarne Giorgio. Variation of body mass in Moorhens Gallinula chloropus wintering in a temperate area. In: Revue d'Écologie (La Terre et La Vie), tome 53, n°4, 1998. pp. 353-365