Nella primavera 1990 sono state raccolte e analizzate 95 uova di 5 specie di uccelli nidificanti in
Lombardia allo scopo di identificare e quantificare la presenza dei metalli mercurio, piombo, cadmio, cromo
in esse. Le specie erano: Germano reale Anas platyrhynchos, Merlo Turdus merula, Gallinella d’acqua Gallinula
chloropus, Cornacchia grigia Corvus corone cornix, Piccione domestico Columba livia domestica. Sono
state rilevate le dimensioni delle uova, è stato calcolato l’indice guscio e il volume e ne sono state ricercate le
correlazioni con le concentrazioni dei quattro metalli. Solo per due specie i coefficienti di correlazione sono
risultati significativi: per la Cornacchia grigia tra il mercurio e indice guscio (P

The Bittern population of a marshland in Centralltaly was censused using a network of listening
stations. This technique appears to be sufficient to quantify the population being examined, but does not
allow an accurate analysis ofthe positions ofthe boorning males.
The data in the literature, dating from 1974, indicate that the population studied had a progressive increase
up to the early 1990s (from O-l to 14-18 males) and then a phase of decline (with 7-9 in 1994). These
variations seem mainly due to the changes in the marsh vegetation. This was positive at first, thinning out
the reedbeds, then negative with their progressive reduction.
However, the role ofprimary irnportance ofthe studi ed population in ltaly has been confirmed.

The Alpine Chough Pyrrhocorax graculus is a social corvid which uses food provided by tourist
activities in mountain regions (e.g. at ski stations, refuse dumps, picnic areas). In order to determine the
impact ofthe human food supply on the Alpine Chough, foraging flock size and distribution were studied in
a tourist region in the Northern French Alps between 1988 and 1992. Alpine Chough attendance at tourist
sites was closely related to human activities. Activity rhytbrn was influenced by human presence on picnic
area in summer. Relations to human activities held at a seasonal scale (such as opening of a ski station) but
not at a daily time scale (such as weekend). Long term trends of Alpine Chough populations since intense
tourist development at altitude are discussed with regard of flock size counts recorded at a same site before
and after intense tourist development.

The phenology and structure ofthe nest-sites of a Connorant colony in dead trees, during 1992-
1993, are described. Sites were c1assified using three criteria: (I) topography ofthe colony; (2) density of
breeding trees; (3) structure ofbreeding trees. Photographs were used to mark the nests during the breeding
periodo The number ofnests increased to a peak in early May and then declined; many nest sites were used
successfully by more than one pair. The structure of nest sites was more important than their position. The
percentage of sites reaching the nest stage decreased during the breeding season. Adult birds showing much
white on the head are more frequent in the centre ofthe colony. Sites taken by breeding immature-plumaged
birds are like those taken by adults, but immatures seem to succeed in building nests and breeding only on
sites of lower quality. Beginning from 1992 some breeding attempts occurred on sites outside the present
colony. Current level of competition between Cormorants and Grey Herons which breed in the same area is
low. Differences between this and a similar German colony are discussed.

Relationships between egg mass, egg composition, hatchling mass, female characteristics and
environmental conditions during egg formation were investigated for Swallows Hirundo rustica in CentraI
Scotland. Egg dimensions were highly correlated with egg masso 60% of variation in egg mass originated
from differences between females. Egg mass was repeatable (repeatability=0.54) for individuaI birds but
was not related to other female characteristics such as measures of structural size. Egg mass was not related
to clutch size, hatchability or position in the clutch. Eggs contained more lipid iffavourable environmental
conditions prevailed during egg formation. Heavier eggs contained more lipid and lean dry component. A
sample of eggs was hatched in a incubator so that hatchlings could be matched with the eggs from which
they emerged. Egg mass explained 60% ofvariation in hatchling masso 79% ofvariation in hatchling mass
was explained by the first component in a principal component analysis which used egg mass, length and
breadth to describe egg size. Heavier eggs produce larger hatchlings which generally grow faster and have
greater survival across 34 studies of non-passerine birds. Although larger passerine eggs produce hatchlings
which are initially larger and grow faster (n=7 studies) this does not lead to increased survival. Hirundines
lay relatively small eggs for their body size although production oflarger eggs was predicted to have little
extra cost for a Swallow and should be advantageous as larger hatchlings would be more likely to survive
periods of food shortage.

The off-nest behaviour of the Little Tem Sterna albifrons was studied in the Axios Delta, a
Macedonian wetland. The time taken up by the following components of this behaviour was measured
during incubation in four nests and during different parts of the day: Away from nest, Shift during
incubation, Chase of intruders, Throwing Sideways, Around nest, Wake Up and fly, Courtship Feeding and
Human Disturbance. Data were analysed by Repeated-Measures ANOV A. There were significant effects of
nest, day and part ofthe day on a number ofthese components of off-nest behaviour. The birds from one of
the nests spent very different proportions of time on the various activities than those at the other nests. The
effects ofthe part ofthe day were clear and some activities exhibited trends: time spent on Away and Shift
typically decreased from the beginning to the end ofthe day, Human Disturbance was diminished in the third
part ofthe day and Wake Up and Throwing Sideways were greater in the middle ofthe day. Despite clear
day effects on many variables there was no regular pattem to these. There was also an interaction of day and
part of the day on Away, Throwing Sideways, Human Disturbance and Wake Up denoting that these
activities were affected by unpredictable events.

The method normally used to measure the wing shape in both live birds and museum skins, is
based on the measurement of the distance between the tip of each primary and the tip of the folded wing.
This method has two essential shortcomings: it does not allow to compare live birds with museum skins and
it is difficult to standardise when different observers are involved. It seems therefore inadeguate for studying
the wing shape variation ofpopulations breeding on a large geographical range. Here we propose to use the
total feather length for measuring the wing shape. This will allow to compare living birds with museum skins
and to obtain comparable results from different ringers.