BIRDS Hertfordshire compares favourably with most other counties in its list of birds, although it has not the advantages of a sea coast. Parti- ally to compensate for this, it has at least two good-sized areas of artificial water, which have undoubtedly contributed towards increasing its list of feathered visitors. Indeed the reservoirs at Tring and Elstree form ex- cellent examples of the methods by which civilization indirectly induces birds to become resident in a place where otherwise they would probably never have come at all, even as accidental visitors. The county of Hert- ford is not from an ornithological point of view particularly well off for rivers, as although there are a good many small streams, few of them are really large enough to be attractive to wildfowl. One may roughly divide Hertfordshire into two districts for the purpose of studying its avifauna the northern, which is chiefly composed of open hilly coun- try, and the southern, which is enclosed and well wooded, with fine parks and commons scattered about it. The first division, which comprises only a small area as compared with the other, practically consists of a range of chalk hills running across the north of the county from east to west : these hills, which somewhat resemble the downs in Sussex and Berkshire, though on a smaller scale, are to a great extent unenclosed, although this is not so much the case now as in former times. Scattered about over these are small plantations, principally composed of conifers, which are the chief strongholds in the county of the long-eared owl (Asia otus). This part of the county was formerly the resort of certain species of birds which love the open country, but these have now unfortunately disappeared be- fore enclosures and improved methods of cultivation. The other division, which is composed of enclosed lands, abounds in hedgerows and woods which form attractive homes for many of our smaller birds. There the avifauna differs considerably from that found further north, as warblers and birds of that description take the place of the finches and buntings of the open country, while on the gorse-covered commons, so abundant in Hertfordshire, one may see the stonechat (Pratincola rubicold), whinchat (P. rubetra)^ grasshopper-warbler (Locustella ncevia) , and nightjar (Caprimulgus europtzus). This part of the county is more or less undulating, and on many of the streams flowing down the valleys one may find the dabchick (Podicipes JJuviatilis) . In the extreme south of the county there is less arable and more grass land, and the woods are as a rule much smaller ; the hedgerows however are well timbered. This is the last haunt of the carrion-crow (Corvus i 193 o
