Small, fierce and beautiful, the merlin adapts to survive

As our coastal mudflats and estuaries fill up with large flocks of wading birds moving in from their northern breeding grounds, they will need to maintain constant vigilance for a small bird of prey, not much bigger than a thrush, that could swoop in amongst their ranks at any time in a daring smash and grab raid.

Size doesn’t matter for the dashing merlin because its small body packs a fearsome punch, favouring a fast low-level attack that will send a feeding flock of dunlins into a panicked scatter. The falcon picks out its fleeing victim from the mass of wheeling waders and tenaciously stays on its tail, weaving this way and that, before plucking it out of the air with its sharp yellow talons. This speed and agility has led falconers to dub the merlin the “pocket rocket”.

There is no doubt that the merlin is a gutsy bird. I remember once in Shetland being dive-bombed by a determined female after having inadvertently strayed near her nest. She chattered her defiance continually and would circle around me on rising wings before making her downward swoop. I also recall a tale from a reliable source of an instance on the Ythan estuary in north-east Scotland when a merlin was so engrossed in its aerial chase of a small wader that the flighty falcon flew straight into a parked car that had its door open.

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Another pair I got to know well on the expansive heather moors of Aberdeenshire would intercept any large bird that ventured onto their territory, including gulls, crows and even once a hen harrier, and mob the avian intruder with relentless ferocity until it had been driven away.

In the Middle Ages the merlin was known as the “ladies’ hawk”, being small and lighter on the wrist than other falcons, its attractive plumage no doubt aiding its popularity. In falconry it was used for catching larks, a supply of which were often kept in an aviary and released particularly for the purpose of hawking.

Although the merlin frequents a wide range of open habitats in other parts of its world range, in Scotland it is essentially a moorland nester, often concealing its ground nest amongst thick heather and preying upon small hill birds such as meadow pipits, skylarks and wheatears.

It will also take butterflies and large day-flying moths but does not predate upon grouse, so poses no threat to game interests. In autumn and winter our merlins generally move to low-lying open countryside and the coast to hunt over farmland, mudflats, salt marshes and estuaries.

It is this reliance on moorland for nesting that has made the merlin a rather vulnerable bird. The highest breeding densities and productivity tends to occur on heather moorland well- managed for red grouse, and it is especially sensitive to changes in such areas, including heavy grazing that limits the amount of long heather required for nesting. On unmanaged moorland, the encroachment of bracken and other plants may result in the ground becoming unsuitable for merlins.

Afforestation can remove good hunting habitat too, but in recent decades it has also provided Scottish merlins with a real opportunity to improve their breeding success, with a growing number of birds mirroring their continental counterparts by now nesting in old crows’ nests on the edge of forestry plantations and feeding on adjacent open ground. These enterprising merlins enjoy greater breeding success than ground-nesting birds, which face the threat of predation from foxes and stoats.

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In reality these Scottish tree nesting birds are returning to their roots, for in times past before large parts of the Highlands and Southern Uplands were felled of trees, merlins would have nested in old bird nests along forest edges.

There are hopes that this re-found trend will enable merlins to extend their range into new areas and thus secure the future of this wonderful and feisty little falcon.