When it comes to predator control, March is the most important spring month, as getting on top of things now makes life much easier later on. The crows and magpies that are already paired up will be looking for new territories or guarding the ones they?ve already got, while rooks and jackdaws will be nesting in earnest. If these nests are successful, there will be lots of extra mouths to feed, and the eggs and chicks of other birds will definitely be on the menu.

Though magpies, which pair up earlier than crows, start appearing before we?ve finished shooting, they don?t really go into the Larsen traps until early March, and even then it?s only a few early nesters. A couple of weeks later, they?re keen to drive off the intruding call bird and go into the traps almost as soon as they?re set, especially if the trap is placed close to the nest or nest site. Now is the time to get your call bird, if you don?t already have one. Most, if not all, keepers will set a trap or two, so if you?re not in touch with someone who traps and can pass on a spare bird, find your local shoot ? there will be someone there who will be more than willing to supply one. I usually get my first one when we catch up after Christmas, but if I don?t manage to get one, I have a friend who has a large area of open access woodland, complete with picnic areas, who can catch them almost to order using bread.

Crows will try to drive off any magpies that are too close to their nests, so I don?t really bother starting on the crows until I?ve caught most of the magpies. When I need a carrion as a call bird, I just swap one that goes into a Larsen trap (after a magpie) with the call bird that was already in there, and then move it to a different part of the estate, and it usually starts catching straight away.

On balance, crows tend to cause me more problems than magpies do. Magpies will hunt every hedge and rough patch in their territory ? which isn?t good for the smaller songbirds, pheasants and partridges that nest there ? while crows tend to favour the more open arable areas. So, in addition to hunting the hedges like magpies do, crows also systematically hunt the middle of fields looking for the nests of birds such as lapwings. If they find a nest, they clear it of eggs, and if they find a brood of chicks, they harry them until the last one is gone ? even good parents such as lapwings will struggle to keep a determined pair of crows away from their chicks.

The other members of the corvid family, rooks and jackdaws, are less of a problem for gamekeepers, but they do cause problems at certain times of year both for us and for our tenant farmers. They take eggs, and somewhat surprisingly, rooks took more eggs from our laying pen when it was open-topped than crows and magpies put together.

Farmers also have problems with rooks and jackdaws. When the corn is drilled and starts to chit, poking through the surface, the birds spot the soft white tips of the new shoots and pull them out to get at the seed corn underneath. They will continue to do so until the crop becomes stronger, gets a decent root down and turns green. They can also be a nuisance by flattening and eating corn ? especially barley ? when it?s at the soft ?milky? stage, by stripping maize plants of their cobs and by pecking holes in silage bags. It seems they are not quite the farmers? friends they are sometimes made out to be.

Difficult to shoot

If rooks or jackdaws get a taste for something, they can be particularly hard to stop. They don?t go into Larsen traps, because they?re happy in flocks and can tolerate each other, and they are difficult to shoot in numbers that will make any significant difference.

I find that the best way to reduce their numbers is by using large ladder-type traps in the springtime. I?ve only got one, but it?s sectional and easy to move around ? I find a movable trap to be more effective than a permanent one because I can take the trap to wherever the rooks or jackdaws are feeding, instead of trying to attract them to where I?ve built the trap. Used properly, these traps will pick up dozens of birds.

I make mine out of ?pen sections?. The six sections (three panels, a door for the frame and two panels to place inside the frame at an angle to take the ?ladder?) can be put on a trailer, and then be taken to wherever they?re needed and put together quickly. Pre-feeding is essential, as is removing any other food sources for a few days until the birds start feeding in the trap. I set mine at dusk and try not to go near the trap again until late afternoon the following day, in case I scare off any birds that are hanging about outside the trap. I usually set and catch for two or three days in a row, and then let the numbers build up for a few days before re-setting. This appears to work better than setting for a week or more at a time, as there are always a few birds still feeding at the trap, which helps to attract any new ones that haven?t found the bait.

I?ve got a small stock of wild pheasants on part of my estate and they ? as well as lapwings and countless other birds ? only manage to hatch and rear successfully because of the huge amount of effort I put into controlling the members of the corvid family that hunt the ground or try to nest nearby. The habitat is good and there?s plenty of food, but without my trapping there would be few wild broods on the stubbles in September. It makes it all the more satisfying to see the few broods that are successful, knowing that they probably wouldn?t be there if it hadn?t been for my work.