262 THE ZOOLOGIST. 



the water, were inadmissible, and the only practical measure appeared to 

 be introducing some live agency (possibly the common carnivorous water- 

 beetles) which might clear the obnoxious plant-eating larvae. To this 

 suggestion I received the reply that ' there were lots of trouts till the 

 Herons came;' — but for reasons (which might give offence if specified 

 here) there were difficulties in the way of having the Herons got rid of. 

 Here we come to what appears to me of a good deal of interest. Besides 

 what is known to, or is before us all, as to partiality cf trout for insect food, 

 on turning to Walton's 'Complete Angler' (7th ed. pp. 302-308), I found 

 a mass of observations on the ' divers kinds of Caddis, or Case-worms . . . 

 which be a choice bait for any fish,' and at page 305 he mentions some that 

 ' be usually bred in the very little rills or ditches,' of which (piscatorially 

 speaking) he writes ' doubtless they are the death of many trouts.' This 

 is followed by directions of how the Caddis-worm is to be ordered, and 

 then thrown * into any great still hole where a trout is, and he will presently 

 venture his life for it, it is not to be doubted, if you be not espied,' &c, &c. 

 Other causes of destruction may just possibly have been present, but the 

 subject having been repeatedly investigated in the course of report to myself, 

 I see no reason at all to doubt that it was the great amount of presence of 

 the Caddis-worms that caused mischief, and Isaac Walton's evidence of the 

 love of trout for Caddis-worms as baits points strongly to their knowledge 

 of the goodness of the larvae for food in more natural circumstances ; aud 

 that in their removal the watercress grower lost very helpful friends. The 

 habits of Herons need no comment, and the sequence of events consequent 

 on local encouragement (beyond what in these days is called ' natural 

 balance') of one large species of birds of special habits, downwards through 

 destruction of insect-eating fishes, and overplus of vegetable-eating insects, 

 to the great pecuniary loss of the grower of the insect-injured crop, is, 

 I think, of some iuterest. — E. A. Oemerod." 



Bird-life in the Dutch Water Meadows. — A writer in ■ The Spectator' 

 of May 23rd last, who though anonymous is evidently an observant natu- 

 ralist, gives a pleasing description of the appearance presented in summer 

 by the reclaimed marshes or "polders" of Holland, which afford such 

 excellent pasturage for cattle ; and from personal observation we can vouch 

 for the accuracy of his description. He says: — " Whitethroats, Linnets 

 Finches, Blackcaps, Thrushes, Flycatchers, Robins, and other hedge and 

 thicket-living birds are absent in a region where dykes take the place 

 of fences, and there is no hedgerow timber. Only in the dense copses of 

 alder, rooted in stagnant water and matted with a jungle of marsh-plants, 

 do the river side warblers appear. There the Sedge-bird, the Reed Warbler, 

 and the Great Sedge Warbler, the finest of all Continental song-birds, except 

 the Nightingale, may be heard at all hours of the day. But in the open 

 'polders' between the long rhines of water which run parallel, like lines of 



