1904. Notes. 95 



Herons in Belfast Lough. 



Some correspondence about Herons that lately appeared under 

 " Nature Notes " in \}^^ Northern Whig induced me to communicate to 

 that Journal my views as to the causes that have led to the greatly 

 reduced numbers of the birds frequenting the bay now as compared with 

 former years, and that communication I have now been asked to repeat, 

 in a slightly extended form, for the Irish Naturalist. 



Thompson (vol. ii., p. 135) records fifty seen at a time on the Co. 

 Antrim side of the bay, within three miles of Belfast, on nth November, 

 1840 ; and on another occasion (p. 133) he reckoned sixty. On 14th 

 November, 1847 (p. 134), he counted forty-two, awaiting the falling of the 

 tide, in a large ploughed field at Parkmount, the seat of H. H. M'Neile, 

 Esq., near Belfast. It is strange that, while mentioning other heronries 

 in the neighbourhood, Thompson does not mention the one at Park- 

 mount, although, as we have seen, he was aware of Herons frequenting 

 the place ; yet from what Mr. M'Neile told me twenty-five years ago, the 

 Herons must have commenced nesting there some twenty years prior to 

 the date last mentioned, namely, about 1827. So recently as in 1878 I 

 have recorded seeing twenty-nine in one afternoon, while now sometimes 

 for weeks I do not see one. I did see one this week, and a few are still to 

 be seen most days on the Co. Antrim side. I attribute the beginning of 

 this falling off to the restriction of the birds' feeding grounds by the 

 railway and other embankments on both sides at the upper ex- 

 tremity of th'e bay; but for the Herons' more recent and almost 

 total disappearance from the upper reaches one must look for 

 other reasons. The " new cut," as it used to be called, and 

 other harbour improvements, culminating in the Victoria Channel, 

 diverted the former flow of the tide and the river from the old tortuous 

 channels ; and, by making an increased "scour," gradually swept the mud 

 or ooze off the banks, and with it the Ribbon or Grass Wrack {Zostera 

 marina) that grew on it. This Zostera was the haunt of multitudes of 

 eels, which formed the principal food of the Herons ; so now that the 

 mud, and with it the Zostera, and following it the eels, have all gone, the 

 Herons have gone too, an interesting and curious chain of circum- 

 stances. The eels have, to a large extent, given place to other fish, and 

 the Herons have been succeeded by a greatly increased number of 

 Cormorants and Red-breasted Mergansers, both of which species obtain 

 their food by diving. We have Thompson's record of the forty-two 

 Herons .seen at one time at Parkmount in 1847. On 22nd March, 1879, I 

 saw twenty-one there in a group, and at the same time there were about 

 twenty-three to twenty-five nests in the place ; while latterly, as Mr. 

 M'Neile kindly informs me, under date 6th February, 1904, twelve is the 

 maximum number seen, barely one-fourth of the numbers there twenty- 

 five years ago. Within the last eight or ten years, Mr. Wilson tells me, 

 the Herons have ceased nesting at Belvoir Park ; but the birds still 

 frequent a lake in the grounds, and also the river Lagan, which bounds 

 one side of the demesne. The birds may often be seen on the stretch of 



