@wAr1948: nie, nie mają znikomego. Kot to szkodnik.
"Predation by domestic cats may threaten even very common species such as house
sparrows (Passer domesticus): In Bedfordshire village of Felmersham in England,
house sparrows made up 17% of the total intake of domestic pet cats (Churcher and
Lawton, 1987). In the British Mammal Society survey 961 out of the 3391 birds
collected were house sparrows (28.3% of avian intake or 6.6% of total intake). Mead
(2000 in: Woods et al., in press) suggests that every year, during the breeding season
from April to August cats are responsible for the death of 9 million house sparrows in
Britain. This predation pressure is significant since there were 2.6-4.6 million pairs of
house sparrows in Britain during 1988-1991 (Gibbons et al., 1993 in: Woods et al., in
press). Hence, cat predation alone could account for most or all of the annual
productivity (Woods et al., in press)."
"Mice and rats were rarely seen
as victims of cat predation although the pest rodent population in the dockyard was
reported to be relatively high (Dards, 1980). This may support the observation that
prey size and difficulty of capture may greatly influence the predation attempts by
cats and that urban cats avoid foraging on large rats (reviewed in: Hall et al., 2000)."
"In Canada, 5 million pet cats kill approximately 140 million birds and small animals
each year (The Cat in Kennel Campaign).
Based on studies from across the US, it is estimated that in the US cats kill over a
billion small mammals and millions of birds each year (Coleman et al., 1997)."
"In California, a two-year study (Hawkins, 1998) was conducted in two parks with
grassland habitat in the East Bay Regional Park District. One park had no cats, and in
the other park there were more than 20 cats that were fed daily. There were almost
twice as many birds seen in the park with no cats than in the park with cats. California
thrashers (Toxostoma redivivum) and California quail (Callipepla californica),
common ground nesting birds were seen during surveys in the no-cat area while they
were never seen in the cat area." pokaż całość