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David Whitby on disease in game birds

Headkeeper David Whitby on the inevitable and damaging effects of disease on game birds.

By now, those of us who are keepers of game have our birds and await (or have already experienced) the inevitable onset of disease; a good year on the rearing field is so often followed by problems in the release pens and vice versa. I suppose the less hardy are the first to succumb to malady, leaving stronger birds that have already built up a resistance to the season’s prevailing parasites. Conversely, if no outbreaks are experienced at the rearing stage there is no resistance and a far greater likelihood of problems post-release.

Game bird diseases have always existed, but nothing like the variety and frequency we suffer today. It used to be that gapes and coccidiosis were the only real problems, but nowadays a whole host of diseases rear their ugly heads. From the laying stock, through incubation, as day-olds and to released poults, our game birds are susceptible at every stage. And it’s not just released game: wild birds of any species may go down with ailments and, though perhaps to a lesser extent, always have.

I shot my first pigeon in 1961. It was a sick bird and at the time pigeons were dying like flies everywhere. I still remember the disappointment of being unable to eat what was just feather and bones. We see similar disease outbreaks in pigeons today with carcasses and sick birds littering the woods. We know the cause to be trichomoniasis, a protozoan parasite that is seriously affecting greenfinch populations. Trichomoniasis is also known as ‘frounce’ and is seen in its latter stages as cheese-type matter blocking the throat and gape.

The keepers of yesteryear had few answers to the problems they faced when their birds became ill – sherry was often a recommended cure-all. In the 1800s my great-grandfather was a beatkeeper at Ken Hill in Norfolk. They had serious disease problems that culminated in a poor season and the entire keepering staff being sacked, despite there being little they could do. Some years later, Sir Lycett Green approached my great-grandfather about a return to Ken Hill as headkeeper (he was at Sandringham at the time). This was the son of the man who had dismissed the entire department; my great-grandfather took the position and remained there until he died, on a shoot day, aged 89.

Stress and cider vinegar

So many of today’s diseases come under the classification of protozoans, single-celled organisms that wreak havoc when not treated immediately. Hexamitiasis, trichomoniasis, coccidiosis and blackhead are just four of the more common ailments that we find ourselves battling. Increasingly it is not a question of will we get a disease outbreak but when, what and how severe? With all protozoans losses may be high, but they are treatable and perhaps to some extent avoidable. Naturally, hygiene plays an important part, along, of course, with overcrowding, access to feed, correct temperature and, linked with that, favourable weather. If birds, for whatever reason, are denied access to a plentiful food supply, you can nearly guarantee an outbreak of one of the aforementioned will occur. This highlights the importance of having plenty of feeders both on the rearing field and in release pens, as bullying may start an infestation that soon spreads. One of the most susceptible times is the changeover from pellets to wheat: it has to be gradual and is often partnered with sickness – some birds just refuse to eat wheat and become ill, sparking an outbreak.

Stress also plays its part. Going to wood is often a likely time of outbreak and many a game dealer has been accused of delivering sick poults when it is the stress of movement that caused the onset of disease.

Malady is not confined to protozoans as bacterial, viral, fungal and, of course, nematode illnesses are all seen from time to time. Some, like the bacteria erysipelas, respond immediately to treatment, others such as the fungal disease aspergillosis or virus marble spleen do not. So many of our problems have been passed on from the poultry industry and, if we’re honest, our game birds are treated as chickens for much of their early lives, and on some shoots for much of their later lives too.

They say an old dog cannot learn new tricks, but a few years ago I started to alternate the acidity of my poults’ drinking water with the use of cider vinegar added every few days. The results, along with the fact we employed a new specialist vet, have been so much improved. There is nothing quite as awful as coming out of a pen with a sack full of dead birds. Losing 10, 20 or an even higher percentage before a bird has even thought about straying does not bode well for a successful season. The best description I heard for the problems we face with our reared game birds is “a natural reaction to unnatural circumstances”. Food for thought.

Serious concerns about kite numbers…

I was quietly delighted a few years ago when I heard my first raven on the estate. I consider myself a part-adopted Kerryman and their call brings back memories of sika stalking in Irish mountains. Then they nested, populations grew and this year nine ewes have been blinded either when lambing or rolling on to their backs. Legally there is nothing at all we can do to the perpetrators. The same applies to buzzards. It was wonderful to see the first pair, now both buzzards and kites are everywhere and wreaking havoc. A friend was speaking to someone from Natural England recently and apparently they are seriously concerned about the impact of kite numbers in certain areas.

This article originally featured in the August 2014 issue of Shooting Gazette.