The Zoologist/4th series, vol 3 (1899)/Issue 693/On the First Primary in Passerine Birds, Hartert
ON THE FIRST PRIMARY IN PASSERINE BIRDS.
In 'The Zoologist,' 1898 (p. 241), appeared a very interesting article by Messrs. A. Gardiner Butler and A. George Butler on the presence of the first primary in the Fringillidæ, Motacillidæ, and Hirundinidæ, in which it has generally been supposed to be absent. Most interesting as this fact is to those who did not know it, and valuable as some of the special observations made by Messrs. Butler are, the discovery that the first primary is present in these families is not new.
In 1888 (Proc. Zool. Soc. Lond. p. 664), Dr. Gadow says of those families in which the first primary has been supposed to be absent, "The tenth quill is, as a rule, reduced to a tiny feather, which is hidden between the 10th covert and outer vane of the 9th quill." From this article we see also that an eleventh primary is frequently present in front of the tenth (our "first") primary, but that this eleventh quill is completely lost in many families of Passerine birds.
Dr. Gadow's valuable article has been, it seems, most frequently overlooked by ornithologists, and I myself did not read it before I had discovered the same facts about the first primary. In Novit. Zool. iii. p. 13 (1896), I said:—"I was rather surprised to find that in the so-called nine-quilled (or rather nine-primaried!) Passeres the tenth primary is not always, nay, not even as a rule, and very likely never, entirely absent, but only much reduced, and often difficult to find, because stiff and narrow and hidden by its longer covert. From these reduced little feathers to those of Pholidauges, Sturnus, or Calornis is no longer step than from the latter to Acridotheres, Basilornis, and Gracula." ... On p. 14 I then acknowledged Dr. Gadow's article at length.
The failure to find our "tenth" primary in certain families is no doubt due to the impossibility of seeing it from below, and to a certain extent to an omission which is very frequently made in natural history, namely, that only a few forms of a supposed group are examined, and that conclusions about the whole group are made from such scanty observations; from the nature of the point in question, which served to characterize the groups, a certain species is afterwards classified, and thus an everlasting circulus vitiosus is entered.
The removal of the under wing-coverts cannot have caused the mistake, as the first primary in most cases where it has been supposed to be absent is lying somewhat above the first functionary long primary, hidden by and somewhat assimilated to the primary coverts.
- Dr. Gadow calls it 10th, as he begins to count them in the middle of the wing, where they meet the secondary quills.—E.H.