of the Pedes scansorii of Birds. 519 
occupation the bird is often engaged for a considerable length of 
time), its weight is thrown backward, and thus the supply of two 
toes behind is rendered extremely necessary for its support: 
What makes me think the wise Author of Nature had this end 
principally in view is, that the Nuthatch, from the want of this 
conformation, is, when breaking nuts, under the necessity of sit- 
ting with its head downwards. | It may be alleged that its flexible 
tail compels it to this position; but, as I have before observed, 
it runs up trees with equal or greater facility than the Wood- 
pecker, notwithstanding that disadvantage. 
-It would be a curious circumstance, and a conclusive argu- 
ment in my favour, should it ever be ascertained that the three- 
toed Woodpecker (Picus tridactylus*), which has only one toe 
behind, bores trees in the attitude assumed by the Nuthatch 
when breaking nuts. | 
I have now brought this letter, which I fear has tired your pa- 
tience, to a conclusion; but as it is upon a subject hitherto not 
sufficiently examined into, you may possibly think it worthy of 
being communicated to our scientific brethren. 
Fam, &c. 
Wrabness Parsonage, Revetr SHEPPARD.. 
April 15, 1818. T " 
* Linnzus, in his description of the Picus tridactylus, says,  Europæus vertice flavo, 
Americanus rubro est." It is worthy of observation, that a fine specimen, brought by my 
brother Edmund Sheppard, Esq., of the Royal Artillery, (whose assiduity in collecting sub- 
jects of natural history when abroad, entitles him to great credit,) from Drummond's Island, 
in Lake Huron, Upper Canada, has the crest, like the European species, of a bright yellow. 
- 
Es 
XXXII. 4n 
