My garden has recently been host to a pair of foxes. The dog in particular was especially bold — to the extent he picked up in his mouth a fat-ball I had left on the lawn for the birds and attempted to bury it beneath an ash tree less than five metres from my window.

His vixen was a more cautious animal, hanging back among the herbage (pictured below). We also get grey squirrel, and these interlopers got me thinking of just how much of a danger they are to our garden birds.

Let us look at grey squirrel first. We all make the assumption that they destroy huge numbers of chicks and eggs but documented evidence is difficult to come by and perhaps their bad reputation is due to our inability to forgive them for being largely responsible for the demise of the red squirrel.

Second, our red-coated friend, often referred as Reynard or Charlie. Foxes are opportunists always on the lookout for a meal but it is worth noting that, as their urban population has risen, so have our garden bird numbers increased. The probability is they rely heavily on human waste such as scraps from dustbins etc.

In a recent, admittedly limited, survey of predated spotted flycatcher nests, the question was put to the audience: which of five predator species was responsible for most of the monitored losses — grey squirrel, jackdaw, cat, jay or great-spotted woodpecker? Most of the audience, including myself, opted for the woodpecker. In fact, claiming some 63 per cent of victims was the jay.

As with so many things concerning our natural world, we still have much to research and understand. Perhaps you have experiences of mammalian predation, and I am interested to hear them. You can use the comments box on The Oxford Times website oxfordtimes.co.uk/leisure/outdoors/ The exciting spring influx of our breeding birds and the passage of migrating birds is about to get serious and if you would like to experience it first hand the Oxford Ornithological Society is running its Farmoor Reservoir Bird Watching Open Day on Sunday, April 25, 9am-2pm, when some of the county’s top birders will be guiding groups across the causeway and into the hides for a free insight into bird identification.

Barry Hudson, Oxford Ornithological Society