Marsh Harrier (Circus aeruginosus): Back from the brink.
THEY WERE HARDENED TWITCHERS, standing in the reception area of the visitor centre at a celebrated Norfolk nature reserve, their binoculars covered with the day-permit stickers handed out at all such places and worn as a type of trophy to exhibit globe-trotting exploits of the past. They were discussing their latest trip to the Outer Hebrides, when I couldn't help but overhear part of the conversation: "So, what did you see; any eagles?" "Yeah," replied his friend. "No goldies, but lots of white tailed. They were like pigeons," he claimed, referring to their apparent commonness. My blood boiled. Complacency can be a parlous condition, for it brings with it a sense of nonchalance; because everything is all right today, it will be all right tomorrow, and the day after that -- next month, next year. It is worrying to witness this attitude emanating from people who should know better, but not unexpected. The white tailed sea eagle was exterminated from the British Isles just over 100-years ago; hard work and round-the-clock protection has seen them reclaim their former stomping grounds on the west coast of Scotland and adjacent Hebridean islands. Unfortunately, many of us have acquired the same attitude towards the marsh harrier.
By the middle of the 19th century the marsh harrier had been eradicated from Britain, the cause almost certainly the draining of its favoured breeding grounds; the fenlands of East Anglia. The birds were seen sporadically over the following decades, although none were know to have taken up residence and bred, rather they were migrants from the Continent, visiting Britain and the fenlands of the east coast during tough winters on the other side of the Channel. But they did return: by the late 1920's there may have been one or two breeding pairs inhabiting the Norfolk Broads. This number may have touched twenty pairs by the 1960's; then it all went wrong again, these meagre figures crashed, this time probably due to pesticides, inappropriate land use, disturbance. Only very recently -- once more through hard work and protection -- have marsh harriers taken another bite-of-the-cherry in the broadlands of Norfolk, where between sixty and seventy pairs breed each year.
They are an easy bird to identify as they hang in the air above the reed and sedge beds, quartering the acres of their territories on long, broad wings. Quivering their tail feathers to finely adjust their positioning, they will stall and hover briefly before plunging into the whispering vegetation, occasionally emerging with a water vole, a coot, a moorhen, even a grass snake. The largest harriers in Europe, they belong to a sub-family of the Accipitridae (hawks, falcons and vultures), the Circus, and are often described as having owl-like facial characteristics. There is no doubt that they possess a distinctive radar-dish casting to their appearance, as do the owls, which most probably serves to accentuate their hearing; a very useful adaptation when your favoured prey lurks at the bottom of tall herbage.
Broadland and fenland sites that contain vast expanses of reed beds and sedge beds are without doubt the best places to begin a quest to observe these handsome hawks. And without a doubt, April is the best month of the year to see them at their most acrobatic: this is the month that the male and female birds perform an exhilarating flight display and are most conspicuous. Soaring to several hundred feet above their chosen nesting place, they will swoop at each other, legs dangling beneath their bodies before partially closing outspread wings and somersaulting earthwards, talons sometimes locked, only releasing from the breakneck stoop moments before crashing into the marsh below. During these dizzying displays, the male bird may even pass a morsel of food to his mate in midair; practice perhaps for when the hen bird is on her nest. (She will call to the male for food and frequently lurch out from her reedy refuge, snatching the offering from his claws.)
Unusually for harriers, the male marsh harrier is not a predominant shade of grey like his cousins the Montagu's, pallid and hen harriers. Instead, he is a striking blend of blacks, rufous browns, smokey grey and white.
With her mate nearby, a female marsh harrier soars over a prospective nest site, checking the immediate area for potential threats. Once a site is chosen, the male will stand sentry whilst she incubates their eggs.
Stalling above the reed beds, a male marsh harrier pinpoints his mate -- sitting beside their partially built nest -- before dropping down to her side with another suitable piece of vegetation to add to the construction.