< ee ee ree r nontmraeire mea SAA One Ne ae é.

fa a ASAT Oo OTN a Elene natn ant Sin A a ee oe or meat

er ee eas Ee Pa OP a a Seg Sat et ae Gp No ESE EE ee

2 os oF ate MIE

ete a as mm Lite a ote

Dos a ere Rs ae ae

as Shaws

20 ae a EE a

*

. A ad satiated ges

Digitized by the Internet Archive — In 2011 with funding from University of Toronto

http://www.archive.org/details/onunnamedpopulatOOsnyd ~

Peet wt eee es, eo en wb, 2)O°ON CON TR TB UT ho ON. 5

EUM LIBRARIES

(L. 1. SNYDER AT tl

ae LI DRARY ROYAI ¢ WINE

il!

Oman Unnamed pienitaie Of the Great Horned Owl

TORON woe. O NTARIO

OYAL ONTAR FO. MUS BUM) — ONT VE RS ht YY) (OOF OF OR ONTO

ee al R ( : 5 M

ars ae

Th Venda H is WW : y | 7 i

Contribution No. 54 LIFE SCIENCES DIVISION ROYAL ONTARIO MUSEUM

UNIVERSITY OF TORONTO

bE: L. SNYDER Curator of Birds On an Unnamed Population of the Great Horned Owl

1961 THE ROYAL ONTARIO MUSEUM

PUBLISHED APRIL 28, 1961 BY THE ROYAL ONTARIO MUSEUM

PRINTED BY THE UNIVERSITY OF TORONTO: PRESS

On an Unnamed Population of the Great Horned Owl

For some years it has been known that a variant of Bubo virginianus, which may be described without detail as grey in general effect but actually patterned with fuscous-black and white, occurs occasionally as a transient within the southern Ontario range of the nominate sub- species. The geographic source of this variant has been presumed to be the coniferous forest to the north. Because of its normal scarcity, hinter- land dispersal and nocturnal habits, specimens from there have accumu- lated slowly. Now a sufficient sample from western, northern and central parts of the province is available not only to demonstrate agreement with transients taken in the south but to reveal that the variant is pheno- typic of a vast area of the more eastern interior north and that the phenotype is as exclusive as that of any race of Bubo virginianus.

A variant presenting similar characteristics to the one in question has been described by Bishop (1931) who proposed the name B. v. leucomelas. This name rests on two transient specimens collected in southern parts of Vancouver Island, British Columbia. Also Taverner (1942, p. 243) lists 17 specimens taken at 13 separate stations from Alaska and the Mackenzie Delta south to southern British Columbia and Alberta which “by description . . . can hardly be separated from” Bishop’s variant. About half of these were secured during the period of the year when the species is sedentary and probably breeding. Thus these are irregulars within the range of two or more geographic races currently recognized. Taverner regarded these irregulars as hybrids between the extensively white B. v. subarcticus' and B. v. saturatus (he

1. Manning (1952, pp. 63-64) states clearly the inapplicability of wapacuthu to the whitish Horned Owl. Further, in this connection, Oberholser (1904; p. 192) implied that young of the Snowy Owl are not white. This is misleading since the first natal down of that species is white. The trivial name of Hoy (1852), subarcticus, is valid as pointed out by Richmond (1902, p. 86). Reference to Hoy’s original description gives assurance by the emphasis on “white and fawn colour” that he was concerned with the Horned Owl which occupies the more northerly plains of the continental interior (not the form described in this paper).

having proposed the relegation of B. v. lagophonus (Oberholser) to synonymy (p. 240) ). No compact breeding range can be ascribed to the “black and white” variants in the west. Furthermore, there is general agreement that a geographic gap exists between the region where they have been found and the region where a similar variant is found in the east.

Taverner (op. cit. p. 242) in discussing the eastern variant re- marked that it is “a very uniform and common type.” He regarded it as a hybrid between B. v. subarcticus and B. v. heterocnemis. His descrip- tion of it is succinct,—it is “too dark for subarcticus, too white for any other race”... and possesses “little or no red of virginianus.”

It is obvious that there is somewhat imperfect geographic sorting of the many forms or “phases” of this polytypic species” but never-the-less geographic correlations are apparent and probably most recognized populations meet the requirements of the 75 per cent rule. The fuscous- black and white variant which occurs across 500 miles of western, northern and central Ontario seems to display as little heterogeneity as any. It is reasonable to conclude that since there is range interruption in the continental interior, B. v. subarcticus intervening, the sporadically distributed counterparts of this population which occur in the far west, cannot be considered the same. Each perhaps represents a similar but separate biological phenomenon, the results being the same except that in the east the variant has acquired homogeneity over a considerable range. It behaves as would be expected of a geographic race in the display of intergradation in border areas where it meets other recog- nized races. For example the whiteness and yellowness of individuals occupying the region along the more northern border between Ontario and Manitoba and in northeastern Manitoba indicate intergradation with B. v. subarcticus. Toward the south in this longitude a lessening of whiteness and a darkening of yellowness indicates a trend toward B. v. occidentalis. Other individuals from the southern part of this region display reddish brown tendencies characteristic of the nominate race, the range of which is contiguous in Minnesota. It is pertinent to remark here that this is the general region where the ranges of geographic races of many species of birds meet and produce maximum mixtures. It is where plains meet forest, where boreal islands are relict though climate is moderate, where “east meets west and north meets south.”

Concerning the rare irregulars found within the range of the form under discussion, Taverner (op. cit. p. 237) lists a specimen, taken on June 20, at Kapuskasing, Ontario, as B. v. virginianus. A December

2. For example, Taverner found virginianus-like specimens from southern Alberta and British Columbia, including Vancouver Island (p. 243).

specimen (R. O. M.) from Swastika, Ontario, is likewise readily re- ferable to that form. It is possible that the range of the nominate race extends north through the eastern clay-belt thus intercepting an east- ward extension of the “black and white” population into northern parts of southern Quebec. This is still to be determined. Another apparently irregular is that of Taverner (Joc. cit.) who lists a specimen from Moose Factory in the Carnegie Museum, taken on July 12, as B. v. subarcticus. Although most museum specimens of this form under discussion have probably been referred to B. v. subarcticus, Taverner distinguished them, as hybrids.

Some fifty mature individuals in the R. O. M. represent both birds established in the region outlined and transients collected more im- mediately beyond. The writer believes that this collection represents an unnamed geographic race for which the following name is proposed:

BUBO VIRGINIANUS SCALARIVENTRIS, subsp. nov.

Type

Adult female, R. O. M. no. 75245; collected February 26, 1948, at Elsas, on the upper Kapuskasing River, in Algoma District, Ontario, by D. G. Waldriff, District Conservation Officer, Ontario Department of Lands and Forests. Sex determination by dissection and measurements from the specimen in the flesh were made by C. E. Hope.

Measurements of the type Wingspread 1340 mm.; length 585 mm.; weight 1155 gms.

Subspecies characters

Dorsally, the normally exposed portions of the feathers fuscous to fuscous-black densely but narrowly vermiculated with white; the under- colour, or basal portion of the feathers, most frequently exposed on the occiput, hind neck and fore-back, approximately clay-colour. Ventrally with fuscous-black (anteriorly) to fuscous (posteriorly) transverse bars, comparatively regular in outline and nearly as wide as the inter- vening white spaces except on the under tail coverts. Usually with little or no pattern of finely vermiculated spots superimposed over the barred pattern. Facial disc pale grey, sometimes slightly stained with warm colour. Feet soiled white, usually sparsely, vaguely and irregularly marked with drab. Distinguished from B. v. subarcticus by dark colour predominating over white and yellow dorsally and by the broader, more regular and darker bars ventrally. In broad terms, the form can be described as more coldly grey with bolder bars below. B. v. subarcticus

5

is extensively white and tawny with more vague and sparse dark mark- ings below. Distinguished from the nominate subspecies by the general absence of rufous in the plumage, the greyness of the dorsal area and the virtual lack of large, vague, finely vermiculated spots superimposed over the barred ventral pattern so characteristic of B. v. virginianus.

Measurements

(Racial intergrades not included. Wingspread, length and weight measurements made in the flesh by the preparator; others by the writer. Bracketed figure = number of measurements, this followed by mini- mum and maximum; the mean in parenthesis. )

é 6; wingspread [5] 1230-1300 (1280), length [8] 518-560 (540), chord of wing [8] 328-355 (343), tail, from external point between central feathers [8] 191-212 (200), culmen, from cere [8] 25-30 (26.7), weight [1, summer] 1275, [4, fall] 1110-1340 (1238), [2, winter] 1239-1418 (1329).

2 2; wingspread [18] 1295-1410 (1361), length [22] 555-600 (578), chord of wing [23] 350-380 (362), tail, from external point between central feathers [23] 205-234 (216), culmen, from cere [23] 28-—32.5 (30.9), weight [1, spring] 1410, [6, fall] 1120-2145 (1580), (12, winter] 1155-2110 (1745).

Range

From near the boundary of Manitoba in northwestern Ontario (and probably in northern Manitoba), east over the Precambrian Shield to near the Ontario-Quebec border (and probably beyond*), north to the Albany River and south to Port Arthur and approximately the Sault Ste. Marie-Lake Nipissing line. Periodically transient south to Lake Ontario, rarely beyond (Coldstream, Middlesex County) and wander- ing east to Brador Bay, Saguenay County, Quebec (Taverner, op. cit., p. 242)* and west to The Pas, Manitoba. Individuals referable to this form are to be expected in northern Minnesota and northern Michigan.

3. There are transient specimens in the R. O. M. which the writer interprets as inter- grades with B. v. heterocnemis. 4. Taverner’s subarcticus x heterocnemis = B. v. scalariventris.

6

Literature Cited

BISHOP, LOUIS B. 1931 Three apparently undescribed owls. Proc. Biol. Soc. Wash. vol. 44, pp. 93-94.

HOY, PHILO R. 1852 Description of two species of owls, presumed to be new, which inhabit the

state of Wisconsin. Proc. Acad. Nat. Sc. Philadelphia, vol. 6, no. 6, pp. 210-211. MANNING, T. H. 1952 Birds of the west James Bay and southern Hudson Bay coasts. Nat'l. Mus. Can. Bull. no. 125, pp. 1-114. OBERHOLSER, HARRY C. 1904 A revision of the American Great Horned Owls. Proc. U.S. Nat’l. Mus., vol. 27, no. 1352, pp. 177-192. RICHMOND, CHARLES W. 1902 The proper name for the Arctic Horned Owl. Proc. Biol. Soc. Wash., vol. 15, p- 86.

TAVERNER, P. A. 1942 Canadian Races of the Great Horned Owls. Auk, vol. 59, no. 2, pp. 234-245.

Sana ma. ve)

— ee

| ; ; 5 re

»

Lt

LIBRAR, ROYAL ONTARIO Mustum

= ae VET SE Cihar

2 8 te <a

NA a i leat

Se am tema are

TROUT, =

a ta ek i i a Rh pe ge PTT Dorney

x

2 = Sawant ee : = => . “ . : : atoe, as ~ gs; = ne nas . - Se ae era

NER OE SOFTENED NIN, SORE F ech aD cia a STEEL I AE

aS

rte all 4 % ‘ * : 4 3 “ = *S 5 % Oe ae ee . a teh ete s 3 - peak Set Pinca a “se : ‘ . eur NN ES nin ORE pe iaet ies ERP RE aL Na cert orem ies , 7 Tt ss oma os yea AE Sate es SEN twas 2 eae : 2 pa CES - : ; si ca WE Fo SLM Bere Lippgeataey Fe dies hee St i eRe oe tee ieee

pape = se oo Saya are Jere henaena st’ SEY? a RX Daas tecit bie te “¢ i eek Biopesty peat 2 Sine rate a a Cheer Tee ree eee ee eS

1 lig ote ote gatenoria