Hillwalkers take note
Tar Isteach's Gay Clery regularly leads bands of intrepid
republicans on expeditions to the hills of Dublin and Wicklow
along routes rich in the history of rebellion and equally rich in
nature's wonders. To mark Easter Week, he reflects here on the
Bonnán Buí, a rare breed of heron and its links to
1916 Martyr Thomas Mac Donagh.
The Bonnán Buí (Yellow Bittern) is of the same family as the Grey Heron that we often encounter on our rambles and the next opportunity you get try to take a closer look at one these wary birds. Quite a number of these herons survive around the city waterways and I used to enjoy watching one regular visitor as it hunted small fish along the Dodder near Rathfarnham.
Herons not only eat fish but also nearly every thing that walks swims or crawls in watery places. The heron doesn't seem to have changed very much from the oldest remains found in London mud and believed to be over 50,000,000 years old! And sure why would they, as it seems that they have been fairly successful at survival and are found in many parts of the world today.
Of the heron family, about 60 species exist, to which the bitterns also belong. Our usual grey heron seems to be one of the biggest, up to 140 cm. long, and like the rest of the family it flies with a distinct ''S'' shape to its neck. This, I'm told, is caused by the sixth neck vertebra being longer than the rest.
Perhaps what makes the herons and bitterns that little bit special is their powder down feathers and pectinated middle claw on each foot! To explain - all birds moult at least once a year, but herons are a little different by having patches of feathers that never moult! These continue to grow and become frayed and powdery, which is just what the bird needs after struggling with some tasty morsel such as a wriggling eel, which causes the birds head to become covered in slime. The bird then sort of ruffles these feathers (mainly breast feathers), thereby creating a mini cloud of dust which clings to the slimy parts and can then be easily combed off by using the above mentioned claw. Pectinated claws occur to some degree in quite a number of different birds.
The grey heron likes to build its nest in lofty trees, whereas the much more secretive bittern hides its nest in quiet reedy places and is extremely difficult to find. A surprised heron usually lumbers off with a great flurry of wings but bitterns usually freeze on the spot and depend on their excellent camouflage to save them in their reedy habitat.
Unfortunately, the bittern hasn't been seen much in this country since about the 1830s. Perhaps its tasty flesh, the increase of the human population, drainage or even climate helped to wipe it out in these islands.
In about 1911, a pair of Bitterns returned to breed on the Norfolk Broads in England. This nest was carefully guarded and now they also breed in Suffolk and elsewhere. The occasional bird has been encountered on this island also, so perhaps sometime in the future our wild places may witness its very distinctive call once again.