2008 NORTHEASTERN NATURALIST 15(2):293–302 Factors Influencing Movement Distances and Home Ranges of the Short-tailed Shrew (Blarina brevicauda) Lowell L. Getz1,* and Betty McGuire2 Abstract - We studied movement distances and home ranges of Blarina brevicauda (northern short-tailed shrew) for 25 years in bluegrass, alfalfa, and tallgrass habitats in east-central Illinois. Whereas habitat and season influenced movement distances, population density and apparent predation risk did not. Specifically, movement distances were larger in tallgrass than in either alfalfa or bluegrass, presumably because of lower food availability in tallgrass as compared to the other two habitats. Movement distances of both sexes were slightly larger during the breeding season than the non-breeding season, perhaps reflecting searching for mates (males) and increased energetic demands of reproduction (females). Home-range areas did not differ between alfalfa (236 m2) and bluegrass (252 m2); we could not obtain reliable estimates from tallgrass. These data add to the limited information available on movements and home-range areas of the northern short-tailed shrew. Introduction Blarina brevicauda Say (northern short-tailed shrew) is one of the more common small mammals in north-central and northeastern North America (George et al. 1986, Whitaker and Hamilton 1998). Although population biology and ecology of the species have been well documented (Getz 1961, 1994; Getz et al. 2004; Hamilton 1931; Lima et al. 2002; Merritt 1986; Pruitt 1953, 1959), there is little information regarding movements and homerange area of the northern short-tailed shrew. Blair (1940, 1941) reported home-range areas for 13 males and 13 females from an old field and for seven males and 10 females from a northern hardwood forest. Platt (1976) estimated home ranges of 16 individuals from an abandoned field, and Buckner (1966) for 34 individuals from tamarack bogs. Hamilton (1931) and Burt (1940) gave anecdotal estimates of home-range area of the northern shorttailed shrew. The home-range areas reported by these studies are widely disparate, ranging from 243 m2 (Whitaker and Hamilton 1998) to 3927 m2 (Buckner 1966). Several factors potentially influence variation in home-range area of individuals within a population: food availability, predation risk, gender, reproductive condition, and population density. Each individual is predicted to adjust its use of space to best suit its own survival and reproduction. Given the limited information available on movements and home-range sizes of the northern short-tailed shrew, even less is known 1Department of Animal Biology, University of Illinois, 505 South Goodwin Avenue, Urbana, IL 61801. 2Department of Ecology and Evolutionary Biology, Corson Hall, Cornell University, Ithaca, NY 14853. *Corresponding author - L-GETZ@life.uiuc.edu. 294 Northeastern Naturalist Vol. 15, No. 2 about how these measures of spatial behavior vary in relation to ecological conditions and reproductive state. During a 25-year live-trapping study of Microtus ochrogaster Wagner (prairie vole) and M. pennsylvanicus Ord (meadow vole), we recorded data from captured northern short-tailed shrews. Although we obtained homerange data from a relatively small proportion of captured individuals, we were able to estimate home-range areas for 204 northern short-tailed shrews over the course of the study. Additionally, we obtained movement distances, an index of home-range area (Slade et al. 1997), for 1664 individuals. We used these data to test the hypotheses that movement distances are larger: (1) where (habitats) and when (seasons) food availability is low; (2) where predation risk is low (dense cover); (3) for males (moving about in search of mates) than for females (restricted to vicinity of nest) during the breeding season; and (4) at low population densities. Study Sites The study sites were located in the University of Illinois Biological Research Area (“Phillips Tract”) and Trelease Prairie, 6 km NE of Urbana, IL (40º15'N, 88º28'W). We monitored populations of the northern short-tailed shrew in three distinct habitats from 1972–1997: Poa pratensis L. (bluegrass), Medicago sativa L. (alfalfa), and restored tallgrass prairie. Getz et al. (1987, 2001) provide detailed descriptions of the study areas; only brief descriptions are given here. Degree and timing of vegetative cover differed among the three habitats (Getz et al. 2005a), and we presume that this influenced risk of predation faced by northern short-tailed shrews because survival was lower in alfalfa, the habitat with the least cover, than in the other two habitats, which were similar in cover and survival (Getz et al. 2004). Vegetative cover in alfalfa was denser from mid-spring (April) through early winter (December) than during late winter–early spring, when much of the surface was exposed. During mid-spring–early winter, alfalfa plants were less than 0.5 m tall and only scattered plants provided cover up to 1.0 m above the surface. Dense vegetation, including a mat of dead grass litter 5–25 cm above the surface, was present throughout the year in bluegrass; larger forbs provided considerable cover up to 1–2 m above the surface during summer–late autumn. Vegetative cover in tallgrass prairie was dense throughout the year. During spring–early summer, grasses formed cover 0.5–1.0 m high; from late summer–early winter, there was dense vegetative cover 1.0–1.5 m above the surface. During the entire year, recumbent dead grasses formed a dense layer approximately 25 cm above the surface. Penetration of light to the soil surface in early spring was 62.9% of full sunlight in alfalfa, 3.2% in bluegrass, and 4.2% in tallgrass (Getz et al. 2005a). 2008 L.L. Getz and B. McGuire 295 Methods Trapping Three bluegrass sites were trapped during the course of the study. A 2.0- ha site (225 trap stations) was trapped from January 1972–May 1997, an 0.8-ha site (72 stations) from June 1977–June 1987, and a 0.5-ha site (60 stations) from June 1977–December 1983 (Getz et al. 2004). A 1.4-ha alfalfa site (140 stations) was trapped from May 1972 to December 1979 and four alternating 1.0-ha sites (one site trapped at a time; 100 stations, each) from January 1980 to May 1997. A 2.0-ha tallgrass site (247 stations) was trapped March 1972–June 1977, a 0.7-ha site (84 stations) from January 1981–April 1987, and two 0.5-ha sites (49 stations, each) from July 1977–May 1997. The location of the sites are shown in Getz et al. (2001). We established a grid system with 10-m intervals in all study sites. One wooden multiple-capture live-trap (Burt 1940) was placed at each station. Each site was trapped for a 3-day period each month. Traps were first set at 1500 hrs and checked at 0800 and 1500 hrs the following three days, for a total of six trap checks. Because the study was designed for voles, cracked corn was used as bait in the traps. Although not an ideal food to keep northern short-tailed shrews alive in the traps, cracked corn has been used to maintain northern short-tailed shrews on a restricted diet in captivity (Martinsen 1969), and winter caches of corn have been reported from northern shorttailed shrew burrows in the field (Whitaker and Hamilton 1998). Vegetation or aluminum shields protected the traps from the sun during the summer. The wooden traps provided ample insulation in the winter, so nesting material was not placed in the traps at any time. Live northern short-tailed shrews were toe-clipped at first capture for individual identification (≤2 toes/foot). Because we monitored large areas each trapping session, field time was at a premium, and because the study focused on voles, we did not attempt to determine the sex of most live northern short-tailed shrews. We recorded sex of live individuals when it was obvious, such as when males had enlarged testes and when females were lactating or clearly pregnant. Most sex determinations resulted from necropsy of animals that died in traps; all such necropsies were performed in the field at the station of capture. All procedures were approved by the University of Illinois Laboratory Animal Care Committee and meet the guidelines recommended by the American Society of Mammalogists (Animal Care and Use Committee 1998). Data analysis The multiple-capture live-traps had gravity doors; many of the northern short-tailed shrews learned to open the doors with their noses and escape from the traps, as evidenced by their odor and feces that remained in the traps. There was also high mortality: 26.8% of individuals caught for the first time were found dead in the traps. Thus, there was limited opportunity for repeat captures within a 3-day trapping session. Of the 1664 northern 296 Northeastern Naturalist Vol. 15, No. 2 short-tailed shrews captured at least twice during a 3-day trapping session, 16.1% were captured three or more times. Only 36 (2.2%) of the individuals were captured at least twice during two consecutive months, and only three were captured three times in two consecutive months; thus, with these few exceptions, our data meet the assumption of independence. We calculated movement distances as the distance between the first two captures of individuals caught two or more times during a 3-day trapping session (Gaines and Johnson 1982, Slade and Swihart 1983); these distances provide an index of home-range area (Gaines and Johnson 1982). In all three habitats, movement distances did not differ between the sexes (see below); thus, for some of the analyses, we combined data for males, females, and individuals of undetermined sex. We used the exclusive boundary method to estimate home-range areas for animals captured at least three times in a 3-day trapping session (Stickel 1954). Owing to the limited number of captures during a trapping session, other methods of estimating home-range area were not appropriate. Further, because of the large movement distances in tallgrass prairie (see below), we could not measure home-range area in this habitat; stations at which we recorded captures were often too distant to plot realistic home-range boundaries. In order to estimate home-range areas in tallgrass, we plotted the relationship between movement distances and homerange area in alfalfa and bluegrass (see below). We then used the mean movement distance (23.8 m) in tallgrass to extrapolate an approximate home-range area for tallgrass. We recognize the limitations of the exclusive boundary method (Stickel 1954) and that it results in only a crude estimate of home-range area. We log-transformed all movement distances for analyses. We changed all values that were “zero” to 0.001 prior to transformation; this adjustment allowed us to test for differences using one-way ANOVAs (followed by Tukey’s honestly significant difference [HSD] post-hoc multiple comparisons for significance at α = 0.05), independent-sample t-tests, and Pearson’s correlation analyses. Because of small sample sizes for individual months, we were unable to use general linear model procedures (Slade et al. 1997) to analyze effects of variables on movement distances or home-range areas. Results Northern short-tailed shrew densities displayed annual fluctuations in all three habitats (Getz et al. 2004). Mean annual peak densities were: bluegrass, 24.2 ± 1.9/ha; alfalfa, 20.9 ± 1.5/ha; tallgrass, 16.2 ± 1.3/ha. Mean monthly population densities during the three months of lowest densities (January–March) were 4.4 ± 0.6/ha, 1.7 ± 0.3/ha, and 2.0 ± 0.2/ha, in bluegrass, alfalfa, and tallgrass, respectively. 2008 L.L. Getz and B. McGuire 297 Within each habitat, movement distances of males and females did not differ (alfalfa: males, 13.8 ± 2.3 m, n = 34, and females, 13.3 ± 2.3 m, n = 40; t = 0.75, df = 72, P = 0.46; bluegrass: males, 15.6 ± 1.1 m, n = 228, and females, 13.5 ± 0.9 m, n = 265; t = 1.56, df = 491, P = 0.12; tallgrass: males, 29.4 + 4.4 m, n = 45, and females, 26.3 ± 2.9 m, n = 52; t = 0.13, df = 95, P = 0.99). Movement distances, all records combined, were significantly greater in tallgrass (23.8 ± 1.6 m, n = 238) than in either alfalfa (14.8 ± 1.1 m, n = 272) or bluegrass (13.7 ± 0.4 m, n = 1,153; F2,1660 = 6.01, P < 0.01; Tukey’s HSD < 0.05). Movement distances did not differ between alfalfa and bluegrass (Tukey’s HSD > 0.05). Movement distances did not differ between winter (December–February) and other seasons combined (March–November) in either alfalfa (winter: 16.0 ± 2.8 m, n = 34; and other seasons: 14.6 ± 1.2 m, n = 239; t = 0.40, df = 271, P = 0.69) or tallgrass (winter: 26.3 ± 3.6 m, n = 53; and other seasons: 23.1 ± 1.29 m, n = 184; t = 0.81, df = 235, P = 0.42). In bluegrass, movement distances during the winter (11.0 ± 0.9 m, n = 261) were smaller than those during the rest of the year (14.5 ± 0.5 m, n = 892; t = 4.74, df = 1,151, P < 0.01). Only data from bluegrass were sufficient to test for differences in movement distances during breeding and non-breeding seasons (males, February–July; females, March–September; Getz et al. 2004). In this habitat, movement distances of females were slightly larger during the breeding (14.1 ± 1.3 m, n = 193) than non-breeding season (12.8 ± 1.9 m, n = 84; t = 2.38, df = 275, P = 0.02); those of males showed a similar pattern (breeding: 16.0 ± 1.9 m, n = 102; and non-breeding: 14.2 ± 1.8 m, n = 126; t = 1.88, df = 226, P = 0.06). Movement distances of males and females did not differ during the breeding season (t = 1.59, df = 293, P = 0.11). Because of small sample sizes from alfalfa and tallgrass, we used data only from bluegrass to determine whether movement distances were correlated with population density (density measures from Getz et al. 2004). These analyses were restricted to April–October to avoid winter conditions, when low food availability may be a confounding factor. Movement distance and population density were not correlated (r = 0.09, n = 133, P = 0.30). When only the years 1982–1984 (years with highest amplitude fluctuations and largest sample sizes for each month during the 25 years) were included in the analyses, there still was no correlation between population density and movement distance (r = 0.01, n = 20, P = 0.98). Home-range areas in alfalfa (236.7 ± 12.8 m2, n = 63) and bluegrass (252 ± 8.1 m2, n = 146) did not differ (t = 1.02, df = 207, P = 0.38). Movement distance and estimates of home-range area were significantly correlated in both alfalfa (r = 0.64, P less than 0.01) and bluegrass (r = 0.69, P less than 0.01). Comparison of the mean movement distance in tallgrass (23.8 m) with a plot of the relationship between movement distances and homerange area in bluegrass and alfalfa suggested an approximate home-range area in tallgrass of 320 m2. 298 Northeastern Naturalist Vol. 15, No. 2 Discussion and Conclusions In general, movement distances and home-range areas of the northern short-tailed shrew were relatively small. Movement distances of 65.6% of the 1664 individuals were 14 m or less, the approximate minimum movement distance able to be discriminated from a 10-m interval between trap stations. Further, 43.5% of the home-range area calculations involved captures at two or fewer traps (≤200 m2 home-range area). Thus, our estimates of movement distances and home-range areas likely represent minimal values. The greater movement distances of the northern short-tailed shrew in tallgrass than in either bluegrass or alfalfa may have resulted from lower food availability in tallgrass. Earthworms are a major food item of the northern short-tailed shrew (Mumford and Whitaker 1982, Whitaker and Ferraro 1963), and whereas Callaham et al. (2003) reported earthworm densities of approximately 75 individuals/m2 in tallgrass prairie soils, Kladivko (1993) recorded earthworm densities of 400 individuals/m2 in bluegrass/clover soils. During winter, northern short-tailed shrews experience greater energetic demands and in response, increase food consumption more than 40% over that during spring and summer (Randolph 1973). Nevertheless, we found that movement distances were smaller during winter in bluegrass, and did not differ between winter and other seasons in alfalfa or tallgrass; these data suggest that, within a habitat, seasonal differences in food availability are insufficient to influence movement distances of the northern short-tailed shrew. Lin and Batzli (1995) listed 21 species of predators known to be present in our study sites: 8 raptors, 5 large carnivores, 3 small carnivores, and 5 snakes. None is a specialist on shrews. Getz (1994) concluded that varying effects of generalist predators were involved in differential mortality of the northern short-tailed shrew among habitats. Raptors and large carnivores forage above the surface vegetation, whereas small carnivores and snakes hunt below the vegetation at the surface. All would be effective in habitats with sparse vegetative cover, such as alfalfa (Getz 1961). In habitats with dense vegetative cover, such as bluegrass and tallgrass prairie, small carnivores and snakes would be more effective than predators that hunt above surface vegetation. We have, however, no record of numbers and types of predators during our study. Movement distances did not differ with respect to extent of vegetative cover, our measure of potential predation risk. If movement distances were influenced by predation risk, then we would expect smaller movement distances where vegetative cover is sparse than where cover is dense (Getz et al. 2005b). However, movement distances and home range-areas in alfalfa, where cover was most sparse and thus presumed predation risk highest, did 2008 L.L. Getz and B. McGuire 299 not differ from those in bluegrass, where cover was dense and presumed predation risk lower (Getz et al. 2004). Further, movement distances in tallgrass were greater than those in bluegrass, even though the two habitats had equally dense vegetative cover. These observations are consistent with previous findings for the northern short-tailed shrew, Sorex cinereus Kerr (masked shrew), and S. arcticus Kerr (arctic shrew). Buckner (1966) measured home ranges for these three species in three plots in tamarack bogs that differed in degree of vegetative cover (i.e., densities of trees and understory, and extent of ground cover) and found no relationship between size of home range and predation risk for any of the species. We predicted that movement distances of males would be greater than those of females during the breeding season because males would be searching for mates and females would be focusing their activity at the nest. In contrast, we found that movement distances of both sexes were greater during the breeding than the non-breeding season (significant for females only) and did not differ between the two sexes during the breeding season. Increased movement and home range area for males and females during the breeding season has been noted for other species of shrews, including Sorex minutus L. (Eurasian pygmy shrew) and S. araneus L. (commons shrew) (Croin Michielsen 1966), and S. vagrans Baird (vagrant shrew) and S. obscurus Bailey (dusky shrew) (Hawes 1977). Increased movement by females during the breeding season is usually attributed to their need to search larger areas for food to meet the energetic demands of pregnancy and lactation (Churchfield 1990). Home-range areas in our alfalfa and bluegrass sites (236 m2 and 252 m2, respectively) were virtually identical to home ranges measured in central New York (habitat not specified, 243 m2; Whitaker and Hamilton 1998) and somewhat smaller than those recorded in old-field habitat (324–637 m2; Platt 1976). Our estimates of home-range areas were substantially smaller than those recorded in old-field habitat (1800–3100 m2; Blair 1940), northern hardwoods (2200–2800 m2; Blair 1941), and tamarack bogs (3927 m2; Buckner 1966). The reasons for such variation in estimates of home-range areas are unclear. At the estimated home-range area in bluegrass, approximately 40 individuals per hectare could be accommodated without overlapping home ranges. This value is almost the maximum density observed in bluegrass during the 25 years of the study (41 individuals/ha, July 1983; Getz et al. 2004). Only the 54 individuals/ha recorded during July 1987 exceeded the 42 individuals/ha that could be accommodated in alfalfa without overlapping home ranges. Only during October 1987 did population density in tallgrass (30/ha) approach the estimated potential to accommodate individuals without overlapping home ranges (31/ha). Whether intraspecific interactions were involved in limitation of population density could not be evaluated from our data. However, the lack of correlation between 300 Northeastern Naturalist Vol. 15, No. 2 population density and movement distance suggests that intraspecific interactions did not have a role in limitation of population density. It appears, therefore, that densities of the northern short-tailed shrew do not normally reach levels that would result in negative effects from intraspecific interactions. Acknowledgments The study was supported in part by grants from the National Science Foundation (NSF DEB 78-25864) and the National Institute of Health (NIH HD 09328), and funding from the University of Illinois School of Life Sciences and Graduate College Research Board. Literature Cited Animal Care and Use Committee. 1998. Guidelines for the capture, handling, and care of mammals as approved by the American Society of Mammalogists. Journal of Mammalogy 79:1416–1431. Blair, W.F. 1940. Notes on home ranges and populations of the short-tailed shrew. Ecology 21:284–288. Blair, W.F. 1941. Some data on the home ranges and general life history of the short-tailed shrew, red-backed vole, and woodland jumping mouse in northern Michigan. American Midland Naturalist 25:681–685. Buckner, C.H. 1966. Populations and ecological relationships of shrews in tamarack bogs of southwestern Manitoba. Journal of Mammalogy 47:181–194. Burt, W.H. 1940. Territorial behavior and populations of some small mammals in southern Michigan. Miscellaneous Publications of the Museum of Zoology, University of Michigan 45:1–58. Callaham, M.A., Jr., J.M. Blair, T.C. Todd, D.J. Kitchen, and M.R Whiles. 2003. Macroinvertebrates in North American tallgrass prairie soils: Effects of fire, mowing, and fertilization on density and biomass. Soil Biology and Biochemistry 35:1079–1093. Churchfield, S. 1990. The Natural History of Shrews. Cornell University Press, Ithaca, NY. 178 pp. Croin Michielsen, N. 1966. Intraspecific and interspecific competition in the shrews Sorex araneus L. and Sorex minutus L. Archives Néderlandaises de Zoologie 17:73–174. Gaines, M.S., and M.L. Johnson. 1982. Home-range size and population dynamics in the prairie vole, Microtus ochrogaster. Oikos 39:63–70. George, S.B., J.R. Choate, and H.H. Genoways. 1986. Blarina brevicauda. Mammalian Species 261:1–9. Getz, L.L. 1961. Factors influencing the local distribution of shrews. American Midland Naturalist 65:67–88. Getz, L.L. 1994. Population dynamics of the short-tailed shrew, Blarina brevicauda. Pp. 27–38, In J.F. Merritt, G.L. Kirkland, Jr., and R.K. Rose (Eds.). Advances in the Biology of Shrews. Special Publication No. 18, Carnegie University, Pittsburg, PA. 486 pp. 2008 L.L. Getz and B. McGuire 301 Getz, L.L., J.E. Hofmann, B.J. Klatt, L. Verner, F.R. Cole, and R.L. Lindroth. 1987. Fourteen years of population fluctuations of Microtus ochrogaster and M. pennsylvanicus in east-central Illinois. Canadian Journal of Zoology 65:1317–1325. Getz, L.L., J.E. Hofmann, B. McGuire, and T.W. Dolan III. 2001. Twenty-five years of population fluctuations of Microtus ochrogaster and M. pennsylvanicus in three habitats in east-central Illinois. Journal of Mammalogy 82:22–34. Getz, L.L., J.E. Hofmann, B. McGuire, and M.K. Oli. 2004. Population dynamics of the northern short-tailed shrew, Blarina brevicauda: Insights from a 25-year study. Canadian Journal of Zoology 82:1679–1686. Getz, L.L., M.K. Oli, J.E. Hofmann, and B. McGuire. 2005a. Habitat-specific demography of sympatric vole populations over 25 years. Journal of Mammalogy 86:561–568. Getz, L.L., M.K. Oli, J.E. Hofmann, B. McGuire, and A. Ozgul. 2005b. Factors influencing movement distances of two species of sympatric voles. Journal of Mammalogy 86:647–654. Hamilton, W.J., Jr. 1931. Habits of the short-tailed shrew, Blarina brevicauda (Say). Ohio Journal of Science 31:97–106. Hawes, M.L. 1977. Home range, territoriality, and ecological separation in sympatric shrews, Sorex vagrans and Sorex obscurus. Journal of Mammalogy 58:354–367. Kladivko, E.J. 1993. Earthworms and crop management. Agronomy guide. Purdue University Cooperative Extension Service, Mt. Vernon, IN. AY-279. Lima, M., J.F. Merritt, and F. Bozinovic. 2002. Numerical fluctuations in the northern short-tailed shrew: Evidence of non-linear feedback signatures on population dynamics and demography. Journal of Animal Ecology 71:159–172. Lin, Y.K., and G.O. Batzli. 1995. Predation on voles: An experimental approach. Journal of Mammology 76:1003–1012. Martinsen, D.L. 1969. Energetics and activity patterns of short-tailed shrews (Blarina) on restricted diets. Ecology 50:505–510. Merritt, J.F. 1986. Winter survival adaptations of the short-tailed shrew (Blarina brevicauda) in an Appalachian montane forest. Journal of Mammalogy 67:450–464. Mumford, R.E., and J.O. Whitaker, Jr. 1982. Mammals of Indiana. Indiana University Press, Bloomington, IN. 537 pp. Platt, W.J. 1976. The social organization and territoriality of short-tailed shrew (Blarina brevicauda) populations in old-field habitats. Animal Behaviour 24:305–318. Pruitt, W.O. 1953. An analysis of some physical factors affecting the local distribution of the short-tail shrew (Blarina brevicauda) in the northern part of the Lower Peninsula of Michigan. Miscellaneous Publications of the Museum of Zoology, University of Michigan 79:1–39. Pruitt, W.O. 1959. Microclimates and local distribution of small mammals on the George Reserve, Michigan. Miscellaneous Publications of the Museum of Zoology, University of Michigan 109:1–27. Randolph, J.C. 1973. Ecological energetics of a homeothermic predator, the shorttailed shrew. Ecology 54:1166–1187. Slade, N.A., and R.K. Swihart. 1983. Home-range indices for the hispid cotton rat (Sigmodon hispidus) in northeastern Kansas. Journal of Mammalogy 64:580– 590. 302 Northeastern Naturalist Vol. 15, No. 2 Slade, N.A., L.A. Russell, and T.J. Doonan. 1997. The impact of supplemental food on movements of prairie voles (Microtus ochrogaster). Journal of Mammalogy 78:1149–1155. Stickel, L.F. 1954. A comparison of certain methods of measuring ranges of small mammals. Journal of Mammalogy 35:1–15. Whitaker J.O., Jr., and M.G. Ferraro. 1963. Summer food of 220 short-tailed shrews from Ithaca, New York. Journal of Mammalogy 44:419 Whitaker, J.O., Jr., and W.J. Hamilton, Jr. 1998. Mammals of Eastern United States. 3rd Edition. Comstock Publishing Associates, Ithaca, NY. 583 pp.