A rapid and unexpected collapse of the lapwing population on the Shannon callows has been identified in a survey of wading birds last year. The decline, described as "alarming", found falls not only in the lapwing population but also lesser drops in the redshank, snipe and curlew populations.
When the Irish Wildbird Conservancy surveyed the area along the Shannon and Brosna callows 10 years ago its researchers found a very large mixed breeding wader population.
Then, there were 342 pairs of lapwing, 383 pairs of redshank, 437 pairs of snipe and 48 pairs of curlew nested on the 3,500 hectares of grassland.
According to a report in the current edition of Wings magazine, published by BirdWatch Ireland, this meant that the area was one of the three most important breeding wader concentrations in Ireland or Britain.
Last year, said the report, a limited survey of the callows, including the whole of the Little Brosna, was carried out by Stephen Heery and Tom Cooney.
It found a massive decline in the lapwing population. They estimated that the callows held no more than 90 pairs and possibly as little as 70.
The report said redshanks were still widespread and were estimated at 223 to 249 pairs. There was a small decrease in snipe numbers.
Mr Heery said in his report that there had been no obvious change in habitat to account for the sudden demise of lapwings, but four consecutive years of April flooding from 1991 to 1994, may have disrupted breeding significantly.
He added that predators may also have exacerbated the problems. Some birds may have moved to a habitat on an abandoned cutaway bog in the vicinity.
"It may seem surprising that a bird as familiar as the lapwing is among the 12 most threatened breeding species identified by BirdWatch Ireland, but concern about this breeding bird is also expressed on lowland grassland in Britain," said the report.
It added that the 1987 survey, initiated by Richard Nairn, was timely in showing that the callows, by their size and nature, have the capacity to hold outstanding numbers of lapwing and redshank.
"The 1997 survey showed that despite declines, the callows of the Shannon and Little Brosna have the capacity to hold very significant numbers," it added.
"For lapwing, it is time to investigate their breeding success and the factors affecting it on the callows, in parallel to similar ongoing studies in Britain and Northern Ireland," said the report.
The report concluded by saying that the lapwing collapse had highlighted the importance of annual monitoring.