Do pheasants have an impact on Brown Hairstreak populations?

[peterc]

It is generally thought that removal and annual trimming of hedgerows are the main causes for the decline of the Brown Hairstreak in the UK.

But could there be another reason for the decline relating to pheasants (even if used for game)? Does anyone know of any evidence of pheasants feeding on Brown Hairstreak larvae? If a particular wood has a large pheasant population knowing that pheasants often inhabit woodland edges could any existing Brown Hairstreak colony be in any danger?

ATB

Peter

[JohnR]

Late summer and autumn are the times when there is an abundance of pheasants raised and released released for shooting. This is restricted to land used for shoots for the birds are fed to keep them near their release pens. The poults love insects and increasingly keepers are sowing nectar and pollen plants alongside the usual cover crops. Pheasants tend to feed in open fields using the woods for shelter and roosting. I would guess that the Brown Hairstreak on Blackthorn is likely to suffer less than other larvae feeding on herbs. The blackthorn hedges here are pretty impenetrable for large birds but probably make a good hunting ground for songbirds. The caterpillar stage of this butterfly is completed before the time that the poults go into the release pens. Wild pheasants successfully rearing a brood are practically a rarity; on a 300 acre shoot here I see about a a dozen wild poults in a good year. Winter hedge cutting has to be the culprit and I would blame the voracious Blue Tits at this time of year for egg losses.

[peterc]

Thank you for your comments, John.

Yes I agree that blue tits, for example, will take Brown Hairstreak eggs.

Since the eggs are often laid very low on blackthorn about 1 metre above ground I suspect the emerging larvae will often feed on the leaves that close to the ground as well. OK, large numbers of pheasants are released in late summer and autumn but there will still be a fair number of them in early summer when the Brown Hairstreak should be in its larval phase and this is the time when few fruits and berries are available for pheasants to eat. The blackthorn may be impenetrable for large birds but can a pheasant resist a juicy caterpillar if it is easy to get to - it wouldn't have to fly in

ATB

Peter

[Gruditch]

Hi Peter,

I think John is spot on with his post. Especially when you consider that Brown Hairstreak numbers crashed with the introduction of mechanical hedge cutting, yet pheasants have been used as a UK game bird since the 1830s.


Regards Gruditch

[peterc]

I don't disagree with John at all and I agree with you, Gruditch, that hedge-trimming is a major cause for the decline of the butterfly. I was just asking the question if pheasants have an impact so anything we can do to stop any further reduction in numbers the better.

ATB

Peter