Volume 20 - N. 2
- Avocetta n. 20 (2) - 1996
Effects of environmental conditions on aerial feeding by Collared Pratincoles Glareola pratincola breeding in southwest Spain
CALVO B, FURNESS R. W.Abstract Read Article Download23 52
During the chick-rearing period, adult Collared Pratincoles Glareola pratincola tended to feed
in the colony or nearby on insects caught in flight. Before and after this period, they often moved further
from colonies to forage in groups over areas of marshes and reeds. Daily activity was highly influenccd.by
weather conditions. Collared Pratincole feeding density was lower on rainy, windy or cloudy or cloudy
days. [n generai, fccding activity increased through the morning up to early afternoon and decreased after
that. Food availability in marsh and reed sites was higher than in the crop site. Apart frorn cereals, few
Collared Pratineoles fed over crops.
Distribution status and breeding of the White Stork Ciconia Ciconia in Greece
TSACHALlDISl E., PAPAGEORGIOU N.Abstract Read Article Download36 59
Two thousand three hundred and eighty seven nests (2387) of White Storks Ciconio ciconio were
found in Greece during the Summer of 1993, Here are presented the geographical distribution and breeding
success ofthe species. The average population density (StD) was found to be 8.4 pairs per 100 Km’, ranging
from 46,05 to 0,09 pairs per 100 Km2 The average nurnber of fledged young per nest (1Zm) was 2,87,
ranging from2,3 to 5,0, The highest nest was found at an altitude of 940 m a.s.l. while the majority ofthe
nests (76%) were found at an elevation <100 m a.s.l, The White Stork prefers as nesting sites electrical poles, both with platform (artificial nests) (53.5%) and without platform (18%). Wetland areas seems to play the 1110stimportant role affecting the density and geographical distribution of the species. The lack of suitable nesting sites appear to be the criticai limiting factor for the species population size.
Extension of post-juvenile moult and ageing of the Cetti's warbler Cettia cetti in northern Italy
PILASTRO A., TASINAZZO S. and GUZZON C.Abstract Read Article Download35 109
The extent of the post-juvenile moult of Cetti’s warbler was studied in northern Italy. Compared
to previous studies, it was found to be more extended than in northem Europe populations, involving body feathers
and most of wing coverts. Moreover, juvenile birds moulted rather frequently all the tertials and up to 5 inner
secondaries. In 6 cases out of 102 examined (4.9%), also 2-5 primaries were moulted. Birds frorn first clutches
moulted significantly more greater coverts than birds from second clutches. Extension ofthe post-juvenile moult
was significantly correlated with the degree of skull pneumatisation in September and October, suggesting that
birds from early clutches have a more extended moult. Moreover, males moulted on average significantly
more remiges and greater coverts than females. Moult limit. i.e. the contrast between moulted adult-like
feathers and unmoulted juvenile feathers. was visible in all examined juvenile birds within greater coverts or,
altematively, within tertials or secondaries. Pre-nuptial moult was restricted both in terms ofindividuals and
number offeathers involved, and never affected wing coverts or remiges. On the basis ofthese results, a new
method for ageing Cetti’s warbler, based on the contrast between moulted and unmoulted feathers, is proposed.
This method allows juveniles to be told apart from adults beyond the completion of skull pneumatisation,
until their first complete moult.
Arthropod abundance and breeding performance of Tits in deciduous,evergreen oakwoods and pine reafforestation of Sicily (Italy)
Massa B., Lo Valvo F.Abstract Read Article Download24 53
The aims of this research, carried out in 1993-96, were: l) to ascertain the existence of
differences in resource abundance between deciduous and evergreen oakwoods; 2) to verify the overlap
degree of the peak resource and the peak-demand of young Tits in the two oakwoods; 3) to study the
breeding performance ofTits (Parus major and P. caeruleus) in relation to resource parameters in woodlots
dominated by trees of different species which are part of the same woodland, namely evergreen Quercus
ilex, deciduous Quercus pubescens and Pinus halepensis reafforestation. In the four years of this research
clutch size, number of fledglings and arthropod abundance were higher in the oakwoods than in the pine
reafforestation; the arthropod abundance coincided with the peak of demand by young, particularly in
deciduous oakwood. Blue and Great Tits breeding in oakwoods appeared to be significantly more successful
than in reafforestation sites; clutches generally were larger and started earlier in the oakwoods than in
reafforestation. Even if differences in the arthropod abundance between deciduous and evergreen oakwoods
were detected, no important differences in the breeding performance were noticed in the four years, while
they were observed in the pine reafforestation in respect to oakwoods, both for Great and Blue Tit.
Changes in density distribution of the Hooded Crow Corvus corone cornix and the Magpie Pica pica in Northern Italy
FASOLA M., CACCIAVILLANI S., MOVALLI C. AND VIGORITA V.Abstract Read Article Download35 52
We describe the density distribution ofbreeding Hooded Crows and Magpies over 12,827 km of planitial landscape,
and we quantify the changes that have occurred since 1980. Nest were censused by
means of winter roadside counts. We tested this technique by applying it to 12 sample zones where the
breeding pairs had been censused during the preceding reproductive season, and we caIculated a conversion
index from winter nest counts to breeding densities. The breeding populations for the entire study area in
1994 increased by 107% of the 1980 population for the Hooded CTOWand by 27% for the Magpie.
Compared to 1980, the areas with high density of Hooded Crows in 1994 expanded north- and east-ward,
while the distribution of the Magpie was similar to that in 1980. The density distributions of both corvids
showed a clear structure with centers of abundance and with concentric bands of decreasing abundance, a
pattern probably determined by gradients of environmental factors. However, the planitiallandscape of our
study area is very uniform, and there is no noticeable gradient to match the density variations between the
two corvids; the variations therefore remain unexplained. The 1980 distribution patterns had suggested that
predation or competition by Hooded Crows could limit Magpie distribution at a geographic scale, but the
1994 data do not confirm this hypothesis.
Food of Italian Sparrow Passer italiae nestlings in CentraI ltaIy
MONDINO L., FRATICELLI F. and CONSIGLIO C.Abstract Read Article Download37 71
The diet of Passer italiae nestlings was studied in a wood of Centrai Italy. All samples
contained arthropods, and shell fragments, seeds and gravel were also abundant. Diet diversity changed
with age, being max imum at about 8 days of age. Diversity also increased with the number of nestlings.
Differences were found with diet of nestlings of Passer domesticus and Passer montanus. Predation on
eggs and nestlings was high.
Feeding success and relationships of some species ofwaterbirds in the «Valli di Comacchio» (ltaly)
BIDDAU L.Abstract Read Article Download19 50
The feeding success of Black-headed gull, Cornrnon tern and Little egret was studicd in the
\”Valli di Comacchio\” lagoon (northeastern Italy), both in presence and abscnce of intra and interspecific
interactions. Sometimes gulls and terns feed on the same areas and on particular occasions aggregate with
other waterbirds, but little is known about the fccding success and behavioural interactions among thern.
The aim of this work was to evaluate the interactions and the feeding success of gulls and terns foraging
sintopically with Little egrets. The Little egret had a very high feeding success, but the intraspecific
territorialism strongly reduced the time available to fish. The Cornmon tern had difficultics to dive because
of the presence of Black-headed gull swimming in the water. The gull was equally successful both in
presence and absence of intra and interspecific competition. Then, the observed feeding rate were highcr
than data frorn literature; this let to suppose that the birds were attracted by a favourable food supply. I
suggest that the observed species are independently attracted to a rich food source.
Passerine birds preyed by the four-lined snake Elaphe quatuorlineata: some remarks on the predatory tactic and the relevance of avian prey for reproductive female snakes
ANGELlCI F.M., FILlPPI E., LUISELLI L.
Shell size relationships in the consumption of gastropods by migrant Song Thrushes Turdus philomelos
GONZALEZ-SOLIS J., ABELLA, J. C. and AYMI R.
Birds in the diet of the Barn Owl (Tyto alba)in an agricultural habitat of northern Italy
GUIDALI F. and PIGOZZI G.
Great Reed Warblers Acrocephalus arundinaceus arundinaceus performing complete remex moult before post-breeding migration
MAGNANI A. and SERRA L.
Dati sulle patologie dei Rapaci in Sicilia
Reproductive parameters and nestling growth in Hoopoe Upupa epops in an area of CentraI ItaIy
BALDI G., SORACE A.
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