To find out whether the surplus of males found in various adult populatiOi1$
of House Sparrow is the resul t of an unbalanced sex ratio at
fledging,the author studied the sex ratio of nestlings and growth and
mortality of males and females in 397 chicks. There waS no evjdence far
an unbalanced sex ratio and no seyual rlifferences in growth or morality
were found. However, the sample to establish the sex ratio is much smaller than the ones cf adult populations in which an unequal ratio was established by others. Sex ratio and competition of nestlings in various
species of birds are reviewed and discussed, It is suggested that an un
balanced sex ratio in House Sparrow fledglings would occur only if food
is abnormally poor, Then females which are smaller in size might be at
a disadvantage in competition with their male siblings.

Metodi semiquantitativi di censimento sono stati applicati, durante il periodo riproduttivo,
in un ambiente di macchia mediterranea bassa degradata, calcolando per
il popolamento ornitico indici di diversità, equirepartizione ed altri parametri.

L’Autore analizza boli di Barbagianni raccolti in due stazioni nell’arco di un an
no. Le prede più numerose sono i Roditori soprattutto in inverno e primavera, seguiti da Insettivori e Uccelli. In estate e autunno aumentano Insetti e Anuri. Il
confronto con dati raccolti nella stessa area 35 anni fa mostra che la dieta del
predatore non ha subito variazioni.