RAUK - Archived Forum - Posts by davecowley:

It would seem to be wise to at least seriously consider the possibility of captive breeding and/ or translocation of commoner species to sites that have been isolated for some time. Sites could be considered as ranging from large areas with a good matrix of links, supporting a high metapopulation - at one end of the scale - through to small sites surrounded by intense urbanisation. These may be as cut off - for population transfer potential - as islands in the sea. For the many and varied range of sites falling inbetween these two extremes, one would expect that making and enhancing habitat links where possible would be the preferred option as far as naturalness goes. One would dare to hope that the forthcoming changes to CAP subsidies (more emphasis on agri-environment works) could go some way to helping bring this about in rural areas.

In cases of isolated sites with no likely potential for linking existed, and where animals might to be introduced to boost the gene pool, one would want to be reasonably sure that the population on site was not dying out due to some other pressure such as cat predation or habitat decline (both of which may be big influences in many cases). Starting a programme of captive breeding and translocation would also imply monitoring of results to evaluate success, and assuming sites remained isolated, one would expect that there would come a time in the future when there would once more be a need for new animals to boost genetic variation of the population, so there might effectively be a need for an ongong cycle of transferes which mimics a natural flow of animals between populations within a meta population. An interesting idea - certainly very artificial (but the problem of isolation has been brought about by humans in the first place) - but it might become vital as a means of saving spicies in certain areas. The alternative could be to resign ourselves to the fact that many reptiles will tend to die out in their surviving pockets in areas with high human populations.

Print size increased to help read.Moderator37837.5463310185


Dave Cowley

Pheasants can range hundreds of metres away from woods and follow field edges, hedges and roads. I have checked some of my own recents sightings on a map and found that pheasants were seen about 500m from the nearest bit of wood - which was actually a tiny isolated pocket of about 30 x 80m. The nearest larger areas of woodland were both about 1km away from the sightings (the woods being about 3 and 5 ha respectively). It would seem likely that the birds range over reptile habitats in a variety of contexts. 

Pheasants spend most of their time on the ground, and I suspect will peck at anything which seems like food - a young reptile is going to be no different to an earthworm to these birds.

Given the relative isolation of many of our reptile sites these days, it seems a distinct possibility that losing even a small but constant yearly number of animals to predation to pheasants, cats and any other similar preditors (what about the red-legged Partridge too, another introduced game bird?), is going to be a big potential cause of reptile decline. One single cat, once it has killed say, a lizard, will come back for more, and I suspect knock out small populations in months or less.

It would seem we need some research on this urgently, and need to think seriously what steps might realistically be taken to deal with predation by such causes.

I think you've hit on something for which there is a lack of a lot of solid data. Beebee and Griffiths (2000) say that they range over 'considerable distances' and mention an ability to return 'home' after a displacement of up to 100 m from a colony focus and add 'presumably because thay know their way'.

Dave Cowley