14 MAY 1921, Page 9

BIRD LIFE IN THE BASSES-PYRRNgES,—BLACK- CAPS AND FIRE-CRESTED WRENS AT

PAU.

THE villa gardens and public parks at Pau abound with . birds of many species—magpies build near the big concert rooms, woodpeckers, blackbirds, chaffinches, sparrows, and tits of three species are very numerous in the park which lies between the town and the golf links. But the species which attracts attention most quickly is the Blackcap Warbler. Every villa garden seems to be occupied by at least a pair of blackcaps, and as one stands on the terrace which commands the famous view of the Pyrenees the song of the birds rises up from many a tree and bush on the steep hillside between the terrace and the railway. And their notes are extraordinarily strong, brilliant, and liquid in tone, while the staves of song are lengthened beyond those which the English blackcaps employ. Most people. who live in the country districts of England are familiar with the note of the blackcap, and its praise as a warbler is in many books. Mr. Warde Fowler, a connoisseur in the songs of birds who can express his knowledge in words of graceful accuracy, Bays : The most gifted blackcaps—for birds of the same species differ considerably in their powers of song—excel all other birds in the soft quality of their tone, just as a really good boy's voice, though less brilliant and resonant, excels all women's voices in softness and sweetness. So far as I have been able to observe, the blackcap's voice is almost entirely wanting in that power of producing the harmonic] of a note which gives a musical sound its brilliant quality, but this very want is what produces its unrivalled mellow- ness." (A Year with the Birds.) But the blackcaps of the Pyrenean district seem to combine both brilliancy and sweetness of tone. This may, in part, be due to the still atmosphere, for it is rarely that the wind blows roughly at Pau, and in part to the houses, cliffs, and hillsides, which provide such good auditoriums for their voices ; yet after making allowance for these favouring circumstances it would seem that all of the singers are what Mr. Wavle Fowler calls " the most gifted."

They have also the stimulus of rivalry, for none need sing alone, and generally each male bird can hear half a dozen rivals endeavouring to surpass him in loudness and variety of utterance. The result is " a charm," as the Berkshire folk call a bird chorus, lasting from early morning till midday and again from late afternoon till dusk, beyond any that the writer has heard in the British Isles. These warblers are resident in the Basses-Pyrenees and begin building their nests before the first of their relatives reach our shores. A nest with three eggs was found in a wood on the Cotteaux, the hills beyond the Gave de Pau, on March 22nd, and a bird was sitting on her four eggs in the willow scrub near the river a few days later. They did not seem to trouble themselves greatly about concealing their nests even when these were placed beside a footpath or road, and showed an indiscriminate taste in the sites selected. Some nests were in bramble bushes as in England, but others were found in laurels, osiers, privet, bamboo, and one in a delightfully picturesque position, in the trailing ivy that covered the face of a great sandstone rock beneath which a spring flowed forth. Many of the eggs were of that beautiful red variety which is so scarce in England, a delicate salmon pink ground colour, with markings of a brick red and spots of dark purple brown—the "pattern," if one may call it so, being the same as that of the normal type of blackcap's egg, which has a marbling or clouding with darker tints of olive brown or yellowish brown on a ground colour of dull white. But in place of this uninteresting series of tints we have in the red variety a charming sequence of pink and rufous, which is rarely seen among the eggs of birds. The red-backed shrikes possess the same capacity for laying at times eggs of a red variety. Their normal type of egg is of a yellowish tint with markings in grey, ash colour, and buff, but, like the blackcaps, they can at times change from the yellow to the red type. How and why this occurs no one seems to know. The tree-pipit's eggs vary from red to dark purple, and cuckoos are a law unto themselves. They can produce " harmonies " in grey, brown, green, red, and even blue so as to avoid abrupt contrasts with the egg; of the foster-parents of their voracious offspring, and one can assign a cause for these variations. But why should blackcaps and red-backed shrikes depart from the usual custom of nest-building birds and lay these reddish eggs There is another and very different song heard frequently, both in and near the town and also among the woods of the hills—the high-pitched song of the Golden and Fire- crested Wrens. This is so high in pitch that it fills in the bird scale nearly the position which the squeak of a bat takes among that of animals—one so high that only a keen ear can detect it. There is not much song, but it brings back to the writer many pleasing memories, for it is associ- ated with wild districts as well as our own home gardens. For these tiny birds, the smallest of all European species, haunt the fire woods of the mountains and are as much at home in lonely districts as they are among the cedars and yew trees of ancestral homes. In the British Isles fire- crested wrens are scarce, while their relatives are numerous as their ranks are recruited in autumn by vast quantities of immigrants from the Continent. The flight of these little birds, whose length is about 3i inches and total expanse of wing not much above 6 inches, across the North Sea is one of the marvels of migration. The writer was crossing from Denmark to Harwich in 1898. On October 5th, when the log marked 202 miles from Esbjerg, .a gold crest came on board. The steamer was travelling at 13 knots, and the little passenger stayed on the ship while it covered forty miles. Then he voted it too slow and pushed on ahead.

To return to the Pyrenean district. Here the fire-crested wrens seem to be the more plentiful of the two species. Many frequent the tangled woods which cover the steepest slopes of the lower hills, those lying between Pau and the big mountains. Yet these woods are of deciduous trees with undergrowth of acacia, hazel, chestnut, and most tangled and thorny blackberries, and lack the coniferous trees which the gold crests usually haunt. It was in great clumps of blackberry bushes that two nests were found, and a third was discovered in the wild clematis clustering round a small tree-trunk. The eggs are more pink in hue than those of the gold crest, and some are quite thickly covered with red-coloured spots at the larger end. The birds are early nesters, and eggs were found on March 26th. There is no European bird that builds a more beautiful nest than their pendent cradle of moss, and none that lays a more tiny egg. Mr. Seebohm gives their measure- ments as from 0.56 to 0.5 inch in length and from 0.45 to 0.4 inch in breadth. We may see what these measurements mean if we take a sixpenny piece and arrange the eggs upon it. There is ample room for two of them to lie side by side, but if placed end to end they exceed the diameter of the sixpence. Still, with a little care in arranging. these tiny morsels of shell we found it possible to balance four of them upon the surface of the coin.