Natural History of the Brush Mouse (peromyscus Boylii) in Kansas With Description of a New Subspecies

Part 1

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UNIVERSITY OF KANSAS PUBLICATIONS MUSEUM OF NATURAL HISTORY

Volume 14, No. 6, pp. 99-110, 1 fig.

December 29, 1961

Natural History of the Brush Mouse (Peromyscus boylii) in Kansas With Description of a New Subspecies

CHARLES A. LONG

UNIVERSITY OF KANSAS LAWRENCE 1961

UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

Editors: E. Raymond Hall, Chairman, Henry S. Fitch, Theodore H. Eaton, Jr.

Volume 14, No. 6, pp. 99-110, 1 fig. Published December 29, 1961

UNIVERSITY OF KANSAS Lawrence, Kansas

PRINTED BY JEAN M. NEIBARGER, STATE PRINTER TOPEKA, KANSAS 1961

28-8518

Natural History of the Brush Mouse (Peromyscus boylii) in Kansas With Description of a New Subspecies

CHARLES A. LONG

In order to determine the geographic distribution of the brush mouse in the state, 15 localities, chosen on the basis of suitable habitat, were investigated by means of snap-trapping in the winter and spring of 1959, spring of 1960, and winter and spring of 1961. Variation in specimens obtained by me and in other specimens in the Museum of Natural History, The University of Kansas, was analyzed. Captive mice from Cherokee County, Kansas, were observed almost daily from March 27, 1960, to June 1, 1961. Captive mice from Chautauqua and Cowley counties were studied briefly. Contents of 38 stomachs of brush mice were analyzed, and diet-preferences of the captive mice were studied. Data from live-trapping and from snap-trapping are combined and provide some knowledge of size and fluctuation of populations in the species.

Examination of the accumulated specimens and the captive mice reveals the occurrence in southern Kansas of an unnamed subspecies, which may be named and described as follows:

#Peromyscus boylii cansensis# new subspecies

Type.--Male, adult, skin and skull; No. 81830, K. U.; from 4 mi. E Sedan, Chautauqua County, Kansas; obtained on December 30, 1959, by C. A. Long, original No. 456.

Range.--Known from 3 mi. W Cedar Vale, in Cowley County, Kansas, and from the type locality.

Diagnosis.--Size medium (see Table 1 beyond); underparts white; upper parts Ochraceous-Tawny laterally, becoming intermixed with black and approaching Mummy Brown dorsally (capitalized color terms after Ridgway, 1912); eye nonprotuberant; tail short but well-haired distally and usually less than half total length; nasals long; cranium large.

Comparisons.--From P. b. attwateri, the subspecies geographically nearest cansensis, the latter can be easily distinguished by the less protuberant eyes and relatively shorter tail (91 per cent of length of head and body; in topotypes of P. b. attwateri from Kerr County, Texas, 104 per cent; in specimens of P. b. attwateri from Cherokee County, Kansas, 103 per cent). P. b. cansensis is darker than P. b. attwateri and darker than P. b. rowleyi, the palest subspecies of brush mouse, which occurs to the westward. The skull and nasals (see Table 1) in adults of P. b. attwateri from Cherokee County average shorter than in cansensis.

Specimens examined.--Total, 26. Cowley Co.: 3 mi. W Cedar Vale, 16. Chautauqua Co.: type locality, 10.

TABLE 1. AVERAGE AND EXTREME MEASUREMENTS OF SPECIMENS OF P. B. CANSENSIS, OF P. B. ATTWATERI FROM CHEROKEE COUNTY, KANSAS, AND OF TOPOTYPES OF P. B. ATTWATERI LISTED BY OSGOOD, 1909.

====================================================================== | P. b. cansensis | P. b. attwateri +-----------+---------+----------+---------+----------- |Three miles| Type | Both |Two miles| Type | west of |locality |localities|south of |locality |Cedar Vale | | | Galena | ---------------+-----------+---------+----------+---------+----------- No. specimens | 11 | 7 | 18 | 20 | 10 | | | | | Total length | 180.5 | 176.7 | 179.1 | 186.2 | 196.0 | 170-199 | 166-188 | ..... | 170-210 | ..... | | | | | Tail-vertebrae | 85.5 | 85.0 | 85.3 | 94.5 | 100.0 | 72-101 | 75-93 | ..... | 83-104 | ..... | | | | | Hind foot | 23.1 | 23.6 | 23.3 | 23.8 | 21.0 | 22-24 | 22-25 | ..... | 22-25 | ..... | | | | | Ear from notch | 18.2 | 19.1 | 18.5 | 18.4 | ..... | 17-19 | 18-21 | ..... | 14-21 | ..... | | | | | Greatest length| 27.9 | 28.3 | 28.1 | 27.8 | ..... of skull | 26.8-29.0 |27.9-28.9| ..... |26.6-29.1| ..... | | | | | Length of | 10.4 | 10.2 | 10.3 | 9.9 | ..... nasals | 9.9-10.8 | 9.5-10.7| ..... | 9.1-10.4| ..... | | | | | Zygomatic | 14.3 | 13.5 | 13.9 | 13.8 | ..... breadth | 13.9-15.0 |13.0-13.9| ..... |13.3-14.4| ..... ---------------+-----------+---------+----------+---------+-----------

Distribution of Peromyscus boylii in Kansas

The subspecies Peromyscus boylii attwateri is known in the state only from Cherokee County, the southeasternmost county in the state. Probably the only locality where the brush mouse occurs in that county is on the systems of cliffs along Shoal Creek, southward from Galena, to the eastward of Baxter Springs. This is the extent of the known range, and in my opinion the probable range, of P. b. attwateri in the state (see Fig. 1). Cockrum (1952:fig. 49) by mistake mapped the species from west of Baxter Springs in Cherokee County.

Osgood (1909:149) recorded the subspecies P. b. attwateri from Cedar Vale, Chautauqua County, Kansas, but the specimen from there must now be assigned to cansensis on geographic grounds. Probably the specimen was not obtained from Cedar Vale itself for the habitat is not suitable there. Numerous specimens are known from 3 mi. W Cedar Vale, in Cowley County, Kansas, all of which are assigned to cansensis. Osgood's recorded locality is situated between this locality and the type locality of cansensis, which is 4 mi. E Sedan, Chautauqua County, Kansas. The distribution of cansensis also is shown in Fig. 1.

Part 2

The probable geographic range of P. boylii is based on trapping data (see Fig. 1). The brush mouse is confined to systems of wooded cliffs in Kansas. The two subspecies seem to be separated by more than 80 miles of grasslands. Blair (1959) has postulated that in the northeastern part of its range P. b. attwateri is represented by disjunct, relict populations formed by diminishing montane or cool, moist environmental conditions. He has implied that the critical climatic change occurred during post-Wisconsin times, and that the isolation of these populations occurred so recently that no morphological differentiation has resulted in them. Inasmuch as the species is widely distributed in México, the southwestern United States, and in California, and has been recorded from the Pleistocene of California (Hay, 1927:323), it is reasonable to suppose that the species immigrated into Kansas from the southwest and that the immigration was in a generally northward or eastward direction. If long tail and large eyes are specializations for a scansorial mode of life (discussed below), then P. b. cansensis must be considered more primitive than P. b. attwateri for the eyes are less protuberant and the tail is shorter in P. b. cansensis than in the latter. I suggest that P. b. cansensis occurred in what is now known as Kansas before P. b. attwateri entered this area by way of the Ozark Mountains. The occurrence of a mouse of "the truei or boylei group" (Hibbard, 1955:213) in southwestern Kansas in the Jinglebob interglacial fauna of the Pleistocene adds little to support the thesis outlined above, but is not inconsistent with the thesis. Incidentally, the geographic distribution of P. boylii may differ somewhat from that shown by Blair (1959:fig. 5); whereas he has mapped the distribution of P. boylii to show disjunctivity in P. b. attwateri and homogeneity in the distribution of other subspecies of the brush mouse to the westward and southward, disjunctivity actually occurs frequently also in the western and southern subspecies.

Ecology

In Kansas the brush mouse is confined to systems of cliffs, the faces of which range in height to at least 40 feet. The highest cliffs--some approximately 100 feet--on which brush mice are known to occur in Kansas are along Shoal Creek, Cherokee County. The brush mouse is found on low bluffs that are parts of higher systems, but in Cherokee County the mouse was not obtained from low bluffs separated by even a few miles from the cliff-system along Shoal Creek. As implied above the brush mouse is adapted for a scansorial mode of life; but other mice and rats inhabit the rocky crevices of low bluffs. Whereas the brush mouse is well adapted for living on high cliffs it seems that the other rodents are better adapted for life on low cliffs. Sigmodon hispidus was obtained from the low, limestone cliffs mentioned previously. From most low bluffs in southeastern Kansas (and on some high bluffs outside the geographic range of cansensis) Peromyscus leucopus was obtained. In Cowley County the brush mouse was abundant when P. leucopus was not and vice versa during this study. Sigmodon hispidus did not associate with the brush mouse in any area, although S. hispidus was often trapped in grassy areas adjacent to cliffs and on the grassy crests of the hills. Except at the locality in Cherokee County, the pack rat, Neotoma floridana, was found in association with the brush mouse. Microtus ochrogaster was the must abundant rodent in adjacent southwestern Missouri (Jackson, 1907) before Sigmodon thoroughly infiltrated this area and southeastern Kansas. Activities of other rodents may have confined the brush mouse ecologically to cliffs. Although the grasslands are a barrier to further intrusion by the brush mouse into Kansas, one cannot assume that they alone confined the brush mouse to cliffs. Such an assumption would not explain its absence on systems of cliffs similar to and near other systems of cliffs on which it is found in the non-grassy Ozarkian habitats of Arkansas, as was noticed by Black (1937). Such an assumption would not indicate why the size of the cliff-systems is correlated with the absence or presence of the brush mouse on the northeastern margin of its geographic range.

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