Volume 18 - N. 2
- Avocetta n.18 (2) - 1994
The diet of the Chough Pyrrhocorax pyrrhocoraxas indicated by analysis of digested prey remains
MEYER R.M., BUCKLAND P.C. and MONAGHAN P.Abstract Read Article Download47 391
The largely invertebrate food of Red-billed Choughs, Pyrrhocorax pyrrhocorax, living on the
mariti me cliffs and hinterland ofWest Wales and Cornwall was investigated by analysis ofprey remains in
pellet and faecal samples. Undigested material was identified to varying taxonomic levels dependent upon
the degree offragmentation and the skeletal units recovered. This was carried out as part ofa study aimed at
conserving the species at the southern edge of its British range, and assessing the feasibility of reestablishment
Direct observation showed that, in the breeding season, ants were a major resource, but their absence from
faecal samples suggested that they are fed exclusively to nestlings. Otherwise, beetles and dipterous larvae,
especially tipulids, were predominant foods. The majority ofthe prey identified in this study are associated
with well-grazed rough pasture and maritime cliffs. Dung fauna apparently guarantees a food supply through
lean periods. The importance of earthworms is ambiguous: direct observation and faecal evidence suggest it
was a regular and important source ofwinter protein, possibly when cerea l grain was unavailable.
Distribution and population-size of colonies of Yellow-Iegged Gull Larus cachinnans michahellis breeding in North-Eastern Adriatic sea
BENUSSI E. and BRICHETTI P.Abstract Read Article Download15 36
The distribution of colonies of Larus cachinnans michohellis in the North Adriatic is related to
the vegetation and the presence/absence of human interference. Strong increases in recent years are noted
and an estimate for the Northern Adriatic population (40,000 – 50,000 pairs) is given.
Winter sympatry of two Reed bunting (Emberiza schoeniclus) subspecies in the Venetian lagoon
AMATO S., TILOCA G. and MARIN G.Abstract Read Article Download24 51
Morphometric data were taken on 403 specimens of Reed bunting, mist-netted during a 7 year
peri od on the northern border ofthe Venetian lagoon. Two morphs could be clearly identified on the basis of
bili depht and wing lenght. The large-billed, short-winged morph (E. schoeniclus intermedia) was caught year
round, while the other (E. schoeniclus schoeniclus) was caught only from October to March. The distributions
ofbill depth ofthe two morphs showed some overlap that may suggest hybridization: birds of intermediate bili
size, however, were never caught in summer months and their wing lenght was that of E. S. schoeniclus.
Some comparative aspects of the breeding biology of Black-headed Gull (Larus ridibundus), Common Tern (Sterna hirundo) and LittleTern (Sterna albifrons) in the Lagoon of Venice, NE Italy
SCARTON F. ,VALLE R. and BORELLA S.Abstract Read Article Download12 37
During the years 1989-1992 three species of Laridae and Sternidae breeding in the lagoon of
Venice were studied. The breeding population of L. ridibundus increased steadily through the period of
study, whereas S. hirundo was stable and S. albifrons decreased. Alrnost ali of the colonies were closely
clustered in the southern lagoon, where hurnan disturbance is less heavy. Colonies were located on a few of
the apparently favourable sites. Colony size was significantly higher in S. hirundo (90.8 ± 80.1, n=45) than
in S. albifrons (51.9 ± 72.3, n= 12) and in L. ridibundus (26.3 ± 42.5, n=20). S. hirundo was significantly
associated with L. ridibundus, whereas S. albifrons avoided the occurrence ofthe latter species. Site tenacity
did not differ arnong species, with the rnajority of sites being occupied only for one or two years.
Suggestions for the protection ofthe colonies are proposed.
Su una collezione di Mallofagi dei Caradriformi: 8 taxanuovi per l'Italia e review delle specie
MANILLA G. , BACCETTI N.Abstract Read Article Download14 52
Da 41 esemplari di uccelli appartenenti a 22 specie di Caradriformi, di cui 19 osservate in Italia
e 3 in Somalia, sono stati raccolti 99 esemplari di Mallophaga riconducibili a 23 specie (5 Amblycera, 18
Ischnocera), di cui almeno 8 risultano essere nuove per la fauna d’Italia: Actornithophilus pustulosus (Piaget
1880), A. tafani (Schrank 1803), A. umbrinus (Burmeister 1838), Carduiceps meinertzhageni Timmermann
1954, Cummingsiella ovalis (Scopoli 1763), Koeniginirmus eugrammicus (Burmeister 1838), Quadraceps
fissus (Burrneister 1838), Q. similis (Giebel 1866).
Dependence of Yellow-Iegged Gulls (Larus cachinnans) on food from human activity in two Western Mediterranean colonies
BOSCHI M., ORO D. and RUIZ X.Abstract Read Article Download16 60
The diet of tledging chicks of the Yellow-Iegged Gull (Larus cachinnans) was studied in the
Medes Islands and the Ebro Delta, two Northwestern Mediterranean colonies with differing ecological characteristics.
The diet ofthe Medes Islands colony showed a higher biomass percentage oftip food than from
the Ebro Delta colony. At the Ebro Delta, chicks consumed a higher biomass percentage ofpreys from channel
s, mainly mullets (Mugil sp.) and showed a higher foraging niche width. The consumption of garbage
from refuse tips seems to affect the growth patterns in both populations.
The breeding biology of Dupont's Lark,Chersophilus duponti, in Europe
Herranz J., Manrique J., . Yanes M. and Suarez F.Abstract Read Article Download19 107
Very little published information exists concerning the reproductive biology of Dupont’s Lark,
Chersophilus duponti, and what is available largely refers to the North African population. Here we present
data frorn 33 nests found in southeastern (n= 15) and centraI (n= 16) Spain between 1989 and 1993.
The reproductive period extended frorn mid March lo early July, a month longer than the orth African
populations. The laying peri od in SE Spain started more than a monrh earlier than in centraI Spain. Nests
were placed on the ground, nearly always partially covered by shrubs (88 %), and oriented to the W, or
E (84%) of the closest plant. In SE Spain, this species appears to select nest site positions covered by
shrubs 7-12 cm in height. o selection was evident in centraI Spain, where shrub height rnay be closer IO the
optirnurn required. Mean clutch size (3.6±0.6 sd) was larger than that reported for North Africa, but no
differences were found between the two areas in Spain. lndications ofasynchronous hatching were found,
and appear to depend on clutch size. Mean egg length and width were 0.5 mrn greater than those reported
previously. The incubation peri od was 12-13 days. Nestling period was very short (8 days). est mortality
was extremely high (84%), but egg hatchability was high (95.7%), and no nestlings starved (n=32).
Coleopteran and lepidopteran larvae forrn 50%. of nestling diet, bui araneids (especially Lycosidae) are
particularly important early in the nestling periodo
Maladaptive adoptions in the Hooded Crow Corvus corone cornix
BAGLlONE V.,PIERI M. and BOGLIANI G.Abstract Read Article Download13 51
Three cases of post fledging adoption were observed in 13 nests located in a northern ltalian
study area, where Hooded Crows nest at a high density (6.7 nests per km\”), Adoptions occurred imrnediately
after fledging; any later atternpt ofyoung to obtain food frorn adults other than own parents was unsuccessful.
Feeding frequency was not different between adopted young and true offspring. Feeding performance
before tledging did not di ffcr bctween the pairs frorn which the adopted young originated and those that
becarne foster parents. lt is presurned that Hooded crows lack the ability to recognize their offspring and
adoptions are a maladaptivc phenornenon due to the high nesting density.
Wasteland bird use. Evidence from the NW Mediterranean coast (Genoa, Italy)
BORGO E., BURLANDO B., CORNARA L. and SPANÒ S.Abstract Read Article Download13 39
Bird occurrence was recorded from January 1989 to June 1991 in a wasteland area located on a
sea embankment within a dammed sea basin close to the city of Genoa. The study area was visited almost
weekly, globally recording 173 species whose occurrence ranged from a few to more than one thousand individuals
at a time. Regularly detected species showed seasonal occurrence or seasonal fluctuations in numbers
of individuals. Bird communities also showed seasonal turnover as testified by the cyclic trend ofthe
herbivores/carnivores ratio. A description ofthe year succession ofbird communities was achieved by correspondence
analysis between months and a total of69 most common species. The first axis (37.6% ofinertia)
displayed species typical of different seasons, while the second one (22% of inertia) was related to the
transient occurrence of migrant species. The most complex bird community was that of wintering species,
mainly divided into sea birds and a crowded group of passeri ne species, whereas the warm season cornrnunity
was less defined, excluding the Ringed Plover and the Short-toed Lark which bred in the area.
Additionally, the area was also used as a refuelling ground by many migrant species, especially wetland
birds when it was flooded by rain. Based on these data, and considering natural environment dcpletion, the
value of wasteland as wildlife habitat and the opportunity of planning the occurrence of low-disturbance
plots within heavily urbanized areas is discussed.
Prima nidificazione di Lanario Falco biarmicus in provincia di Siena e note sulla locale distribuzione storica
MORIMANDO F. , PEZZO F., DRAGHI A. e FRATALOCCHI G.
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