Phylloscopus rufus
This tiny bird is by far the most numerous of our summer visitors, and is greatly in excess of the Willow Warbler. In the shrubberies at Stone Hall, in the spring of 1885, we noticed eleven nests of the Chiffchaff, and only one of the Willow Warbler, and this, we think, is an approximation to the relative numbers in which these birds occur.
From our experience in various parts of England, we have come to regard the Chiffchaff as more a bird of the hills, and the Willow Warbler as belonging to the plains. In North Devon, where we once resided, it was moderately hilly, and there the two birds were met with in about equal numbers. Where we are living now, on the Radstock coal measures some 500 feet above the sea-level, the Chiffchaff is very numerous, and the Willow Warbler is seldom seen, just as is the case in North Pembrokeshire. In his north-eastern corner of the county, when he was at the other side of the Precelly Mountains which greatly influence the distribution of the Warblers with us, cutting many species entirely off from our northern and central districts, Mr. Dix had failed to notice this preponderance of the Chiffchaff we have pointed out. He observes of the Willow Warbler: " Much less numerous than in the east of England;" and of the Chiffchaff, "This is about equal in number to the Willow Warbler," and he considered that the Chiffchaff was more numerous in his neighbourhood in the autumn than it was in the spring. A few Chiffchaffs remain with us for the winter ; we have seen one at Stone Hall in the beginning of January.