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Endangered vs. Table 1.-- Endangered Habitats: A Concepti

2 R. Roy JOhnson , Lois T. Haight; and James M. Simpson3 Num!

Date ext:

l600s Abstract. - Although the great diversity within 1700s riparian ecosystems was recognized earlier, their extreme l800s productivity was not discovered until this decade. The 1900­ highest densities of nesting for North America have 1974 been reported from Southwest cottonwood riparian forests. 1 Complete loss of riverine habitat in the Southwest lowlands Direct could result in extirpation of 47 percent of the 166 2 species of birds which nest in this region. Indirect

INTRODUCTION DISCUSSION Attemp

Since 1600 more than 120 and mammal Extirpation The co species have become extinct while more than species bei 300 are now threatened (Fisher et al. 1969). The extirpation of wild species caused the In addition, dOI~ns of fish~s, am~hib1ans and has been a cause for concern for decades. to begin wo reptiles have become extinct or are endangered People only mildly interested in conservation wildlife in to say nothing of species. Habi­ can bring to mind the examples of the Passenger of the "Red! tat disruption and destruction have been a Pigeon (Ectopistes migratorius - extinct 19l4), use the wore major cause of . Only 24 percent of the Carolina Parakeet (Conuropsis carolinensis­ an unoffici. the birds and 25 percent of the mammals became extinct 19l4), the Dodo (Raphus cucullatus­ Service 197: extinct through natural causes. Of the 76 extinct 1681) and the Great Auk (Pinguinus gered speciE percent of the birds and 75 percent of the impennis - extinct 1844). Dates for extinction according te mammals which died from human related causes, are from Pettingill (1970) and Van Tyne and tion Act of well over half have been through indirect Berger (1971). An entire book has been written U.S. Federal means, such as introduction of exotic speices about the Passenger Pigeon (Schoerger 1955) and life ServiCE and habitat disruption (Fisher et al. 1969 and people are still trying to find out whether great depth IUCN Red Data Books issued periodically). or not the Ivory-billed (Campephilus grams. The principalis) is now extinct. Several recent and Wildlife In an attempt to reduce the numbers of books have been written appealing to citizens Colllllli t tee 00 species which will soon become extinct, se­ of the world to help save these rapidly National Aud veral steps have been taken. A major step diminishing species (Greenway 1958, Fisher et Fund} publis involves the formation of recovery teams, al. 1969, Prince Phillip and Fisher 1970, gered wildli comprised of authorities on a given species, Simon and Geroudet 1970, Tylinek and Ullrich governmental such as the Bald Eagle. The activities of 1972, and Ziswiler 1967). Information from and Wildlife these teams have apparently been beneficial the International Union for Conservation of garding enda in slowing down rates of loss in wildlife Nature and Natural Resources (I.U.C.N.) Red Fish Departm species. However, the efforts of recovery Data Books (issued periodically) presents a U.S. Forest teams cannot possibly prevent continued dismal picture (Table l). Service 1974 extirpation if we continue to disrupt habitat focusing on , through activities such as overgrazing, urban­ Wildlife (Ne, ization, "modern, clean" agricultural prac­ 1 Paper presented at the Symposium on 1972) or eve] tices, dam construction and channelization. Importance, Preservation and Management of the as the Pereg] Continued research is needed to provide answers Riparian Habitat, Tucson, , July 9, 1977. (Hickey 1969: to questions posed by management regarding 2 National Park Service, Grand jDendrocopos means through which critical wildlife habitat National Park Periodically, may be preserved. 3 Associate, Museum of Northern Arizona, species such Flagstaff Fish and Wile

i Arize 1977 • Endan~ Arizona; 3 p.

68 1.--A history of species' extirpation. teams to address the problem of impending ex­ (adapted from I.U.C.N. Red Data tinction have been set up by the U.S. Fish and Books) Wildlife Service for many species of endan­ gered wildlife. For example, several avian species are now being raised by methods of Number of direct intervention such as manipulation (Zimmerman 1976). In addition, several 1 2 Date Direct Indirect agencies are now involved in establishing endangered plant lists. 1600s 21 86% 14% 1700s 36 84% 16% In addition to teams concerned with the 1800s 84 24% 76% protection of terrestrial wildlife, such as 1900­ the Peregrine Falcon and Southern Bald 1974 85 28% 72% Eagle, other recovery teams have been organ­ ized to focus on one or moSe fish species. 1 Direct = Hunting for food or commercial Recently, however (Johnson-) the U.S. Fish causes. and Wildlife Service has designated teams 2 Indirect - Habitat disruption, introduction which focus on river systems instead of of exotics, etc. individual species, e.g. the River Fishes Recovery Team. This approach has been advocated for years by many of us who Attempts to Prevent Extinctions have seen the wholesale extermination of species in certain areas as a result of The concern over the increasing numbers of . Nowhere is this chain species being exterminated in the United States of destruction more certain than in riverine es caused the U.S. Fish and Wildlife Service ecosystems. This has long been recognized to begin work on classification of "threatened" by ichthyologists such as Deacon and Minck1ey tion wildlife in the early 1960's. The 1st edition (1974), Holden and Stalnaker (1975), Minck1ey senger of the "Redbook" was issued in July 1966. We and Deacon (1968) and Sigler and Miller (1963). 1914), use the words "threatened" and "endangered" in ensis­ an unofficial sense (see U.S. Fish and Wildlife us- Service 1973 for official definition). Endan­ Glen Canyon Dam: An Example s gered species are assigned in the United States nction according to the Conserva­ The construction of Glen Canyon Dam on nd tion Act of 1969 and listed periodically in the the above Grand Canyon is an Litten U.S. Federal Register by the U.S. Fish and Wild­ outstanding example of habitat modification. 5) and life Service. It is not our intent to go into The effect on the aquatic ecosystem has been .er great depth regarding endangered speices pro­ devastating. The original heavy silt burden philus grams. The forementioned I.U.C.N., U.S. Fish which rendered the Colorado River "too thick ent and Wildlife Service and others (e.g. American to drink and too thin to plow" is dropped in .zens Committee on International Wildlife Protection, before the water enters Grand National Audubon Society and World Wildlife Canyon. The river waters are now clear. The r et Fund) publish periodic information on endan­ reddish color for which the Colorado was named gered wildlife (e.g. Arbib 1976). Other can be seen only after flooding from tributaries ich governmental agencies besides the U.S. Fish which enter below the dam. This has created rom and Wildlife Service publish information re­ an entirely new riverine ecosystem (Carothers of garding endangered w!ld1ife (Arizona Game and et a1. in press, Dolan et a1. 1974 and in .ed Fish Department 1977-, Behnke and Zarn 1976, press, Johnson and Martin 1976,and Laursen a U.S. Forest Service 1975, U.S. National Park and Si1verston 1976). The management impli­ Service 1974). Symposia are held periodically cations are staggering. On one hand, a new focusing on general problems of endangered riparian ecosystem has developed, protected wildlife (New Game and Fish Department from the scouring and siltation of pre-dam on 1972) or even devoted to a single species such floods. On the other hand this white water f the as the Peregrine Falcon (Falco peregrinus) river has been converted from a stream which , 1977. (Hickey 1969) or the Red-cockaded Woodpecker was warm in the summer and cold in the winter .yon 1Dendrocopos borealis) (Thompson 1971). to a relatively constant 9-10°C (48-50°F) Periodically, reports are issued on endangered along most of its length. The only izona, species such as the Southern Bald Eagle (U.S. family recorded using these cold waters are Fish and Wildlife Service 1976). Recovery Chironomid midges (Stevens 1976) while the

i Arizona Game and Fish Department. ~ Johnson, J. Paper presented at New 1977. Endangered and threatened species in l1exico-Arizona section meeting, the Wildlife Arizona; 3 p. memo Society, Farmington, N.M., Feb 5, 1977.

69 small , Gammarus lucustris, abounds. vention of the use of streams for waste disposal The cold, clear water is conducive to the is gradually becoming an accepted philosophy. rapid growth of exotic species such as rain­ Conversely, industrial, domestic and irrigation bow trout, which commonly reach lengths of demands for water for a growing population con­ more than 2 feet and weigh over 5 pounds tinue to escalate. (personal observation). While exotic fish flourish, our native species are declining. In the 277 miles of the Colorado River in Major Causes of Habitat Loss Grand Canyon National Park several species listed in Fishes of Arizona (W. Minckley The impact of dams on aquatic ecosystems 1973 and pers. comm.) occur either in low has long been understood by biologists even if numbers, or cannot be found at all, e.g. the ignored by dam builders and water users. The ( ~), Bonytail Chub (Q. area above the dam is converted into a lake, elegans), Colorado Squawfish (Ptychocheilus rapidly filling with sediment. The area below lucius) and (Xyrauchen the dam too commonly becomes a dry stream bed, texanus) (Johnson 1977, C. Minckley and Blinn as is the situation with most of the Salt and 1976, Miller 19752, and Suttkus et al. 1976). Gila River dams of the Lower Colorado River drainage. Neither habitat is conducive to most of the pre-dam riverine plants or wildlife. Endangered Species and Related Acts Other rivers are greatly reduced in volume by practices such as pumping of underground water When the Endangered Species Act of 1973 which dries up spring sources, or by modifica­ (PL #93-205) was passed it was hoped by many tion of runoff patterns through overgrazing. of us concerned about extirpation of wildlife The latter often results in the development of that this might prevent further wholesale vegetation types which demand more water than extinctions through degradation of habitat. the original vegetation. The area may be It seemed that the Endangered Species Act denuded, resulting in flash floods followed by combined with the National Environmental quick drying up of streams rather than a slower, Policy Act of 1969 (PL #91-190) should slow steady runoff. The effects of such practices down direct exterminatioI". as well as massive on native fishes have been well documented destruction of the type that has converted (Minckley and Deacon 1968). However, we have nearly all southwestern rivers to poor or only recently begun to understand the impacts impossible habitat for most native species. on riparian ecosystems. Just how effective these laws will be remains to be seen. Legal decisions involving the Recent work by various investigators case of the Tennessee Valley's Tellico Dam on (Boster and Davis 1972, Clary et al. 1974, and the Little Tennessee River vs. the Snail Hibbert et al. 1974) advocates the conversion Darter (Percina tanasi) may have important of shrub types, commonly resulting from over­ implications regarding the future interpreta­ grazing, to grassland. This conversion to tion of Section 7 of the Endangered Species grassland usually results in increased water Act, including possible amendation by congress yield which, in turn, often results in an in­ (Holden 1977). crease in acreage of riparian vegetation (per­ sonal observation, Sierra Ancha and Three Bar It seems inevitable that riverine eco­ watersheds). systems will become the battleground for those advocating the "progress of civilizing Some investigators propose large scale processes," e.g. hydroelectric and irrigation "phreatophyte control" projects as well as the projects. Economic interests oppose those conversion of shrub types to grassland (see who advocate saving a few rivers to protect Ffolliott and Thorud 1974 for discussion). associated wildlife and recreational values These "water salvage" projects are often advo­ and perhaps, "just to let them run." cated even at the expense of both game and non­ game wildlife values. Earlier work commonly The two forementioned acts coupled with featured "pure" scientists as well as "applied" the Wild and Scenic Rivers Act of 1968 (PL scientists, all concentrating on single purpose c #90-542) would seem to be sufficient to reduce management of watersheds and their runoff for further decima·tion of river ecosystems. How­ man, his farms and cattle (Barr 1956, puisberg ever, it is a difficult, uphill battle. Pre­ 1957, and Warnock and Gardner 1960). In recent years there has been a gradual trend toward 6 Miller, R.R. 1975. Report on fishes multiple use of this critical resource, water Il of the Colorado River drainage between Lees (Horton and Campbell 1974). The Arizona Annual 1: Ferry and Surprise Canyon, Arizona. Unpublished Watershed Symposia reflect this change in philo~ E Grand Canyon Natl. Park Res. Rpt. 6 p. sophy (Arizona Water COTDIilission; annually) 1

70 placing increasing emphasis on wildlife values, streamside and/or lake side vegetation. The recreation and even aesthetics (Arizona Water large number of species utilizing riparian wood­ Commission 1972). land has been documented by numerous studies (Carothers and Johnson 1975b). In , Miller (1951) emphasized the importance of Riparian Exploration, riparian avifaunas, stating "the number of Development and Research species of birds associated with riparian woodland is larger than that of any other It seems incredible that man would so formation." However, the extremely high \)adl,; \II.'1.atteat ti'letine. e.CQs"jste:m,s. 'fie. 'nave. ne.nsiti~s 01 TipaTian avian populations was tems used them for exploratory routes, fur trapping, not recognized until this decade (Carothers et en if temporary settlements and forts, agricultural a1. 1974, Carothers and Johnson 1971 and The land and cities. Finally, we have dammed them 1975b, Gaines 1974, Johnson 1970, O'Brien et ke, up, dried them up, and turned them into sewers a1. 1976, and Table 2). below and garbage disposals. bed, The ecological analysis of riparian birds and Early explorers commonly were army officers, is complicated at best. Studies are further er geologists, engineers or "soldiers of fortune" complicated by recent changes, some of which who left incomplete to poor records regarding are related to man's activities and others e. the riparian habitat. This is true throughout which may be operating independently of man . .e by the Southwest. Thus, early notes from rivers One cannot help postulating however, that water such as the Gila (Emory 1858) and even the nearly all of the recorded recent changes are fica­ mighty Colorado (Powell 1961) often mention due to man's activities. For example, there ng. vegetation and wildlife only in general terms. are records for the arrival of several species nt of We do not even have good species' lists for the of birds which have moved into Arizona as than pre-dam ecosystems, much less information on breeding species within historic times. This population densities or other more sophisti­ includes the Mississippi Kite, Inca Dove, 'ed by cated data. Even as late as the 1950's (Woodbury Thick-billed Kingbird, Starling, House Sparrow, slower, et al. 1959) scientists gathered information Great-tailed Grackle and Bronzed Cowbird. ices regarding the area to be inundated by Lake The Starling and House Sparrow are European ,d Powell, above Glen Canyon Dam. However, the introductions. The Inca Dove, Great-tailed have more than 250 miles of river between Glen Can­ Grackle and Bronzed Cowbird are closely acts yon Dam site and the upper reaches of Lake associated with man and his . Their Mead, which were also to be heavily impacted movements are discussed by Phillips et a1. by the dam, were totally ignored. (1964) and Phillips (1968). Other cases are not as clear but may have profound effects on , and Riverine environments, including their the native avifauna. The subtleness with sion riparian ecosystems, have been ignored by bio­ which human activity may affect the natural ver­ logists as well as geologists, explorers and ecosystem can be shown through a discussion o laymen for many reasons. Riparian ecosystems of the Brown-headed Cowbird. Phillips (1968) ter have several characteristics which make them discusses at length the historic expansion of in­ interesting but involved, difficult systems range by Brown-headed Cowbirds. Of the 33 (per­ to study. Riparian habitat may be considered species of Southwestern lowland birds listed Bar an ecotone between the aquatic habitat of the by Friedmann (1929) as hosts to the Brown­ stream itself and the surrounding terrestrial headed Cowbird, 22 (2/3) are obligate or habitat. As such, the riparian ecosystem con­ preferential riparian nesting species. The 1e tains elements of both the aquatic and terres­ role of these brood parasites in reducing .s the trial ecosystems plus retaining unique charac­ populations of riparian birds in the Sacramento .ee teristics found in none of the other ecosys·tems Valley, Ca1iforni~ is discussed by Gaines exemplifying the edge effect. The concept of the (1974). Thus, Brown-headed Cowbirds may be advo­ edge effect is relatively new. Earlier trea­ suspected of causing problems in Arizona and .d non­ tises did not even mention this phenomenon and it other southwestern areas similar to those n1y was not until the mid-1900s that ecology texts, reported for California. ,plied" e.g. Allee et a1. (1949) contained a discussion ,urpose of the edge effect. Odum (1959) defines the for edge effect as "the tendency for increased SUMMARY AND CONCLUSIONS .sberg variety and density at community junctions." recent During our recent analysis of the de­ .rd Ornithologists and birders have long recog­ pendency of the breeding avifauna of the 'ater nized the importance of riparian habitats to Southwest lowlands on water related habitat Annual birds. We chose at random 20 inland Christmas (Table 3), we discovered some sobering facts. philo­ Bird Counts for 1974 (National Audubon Society 166 species of nesting birds were analyzed ) 1975). Nineteen (95%) of the 20 contained from southern Arizona, southern and west , south through the lower

71 Table 2. A comparision of breeding bird densities in selected habitats. (After Carothers and Johnson 1975b). Tal Breeding Bird DensitY­ Habitat Type Males or Estimated (Community) Locality Authority Pairs/40 ha [or 100 acre~ nonriparian ripari~ Boreal Forestl L 2. Spruce-Alpine Fir Arizona Carothers et al. (1973) 178 3. Temperate Forest 4. Spruce-Douglas Fir Arizona Balda (1967) 380 Ponderosa Pine Arizona Balda (1967) 336 Ponderosa Pine Arizona Haldeman et al. (1973) 232 Mature Deciduous West Virginia Audubon F.N. (1948) 724 ~ L Virgin Spruce West Virginia Audubon F.N. (1948) 762 ~ 2. Forest Bird Sanctuary Germany Bruns (1955) 5600 £ 3. Relict Conifer Forest 4. Cypress post climax Arizona Johnston and Carothers (1975) 93 5. Riparian Deciduous Forest 6. Mixed Broadleaf Arizona Balda (1967) 304 7. Mixed Broadleaf Arizona Carothers et aL (1974) 332 B. Cottonwood Arizona Carothers et al. (1974) 847 9. Cottonwood Arizona Ohmart (no date) 683 t Flood-plain Deciduous Illinois Fawver (1947) 216 4 10. I 11. I Temperate Woodland I Pinyon-Juniper Arizona Hering (1957) 33 12. ~ Pinyon-Juniper Arizona Beidleman (1960) 30 13. ~ Encinal Arizona Balda (1967) 224 14. ( 15. Subtropical Woodland 16. Mesquite Bosque (riparian) Arizona Gavin and Sowls (!975) 476 J 17. E Mesquite Arizona Ohmart (no date) - 236 18. F Grassland 19. C Temperate Grassland Arizona Balda (1967) 64 20. \ Tropical Grassland Tanganyika Winterbottom (1947) 4000 f 21. 22. ( Desert Grassland 23. J Yucca/Grassland Arizona Balda (1967) 31 24. Chihuahuan Desert Scrub 25. I! Creosotebush New Mexico Raitt and Maze (1968) 8.5-17.7 26. I 27 ( Sonoran Desert Scrub 1.~. '\ Paloverde/Sahuaro Arizona Tomoff(1974 & pers.comm.) 105-150 29. ") } Temperate Marshland 30. F Cattail Marsh Arizona Carothers and Johnson (1975b) 175-176 31. Cultivated, Urban and Suburban Lands Park (zoological garden) Germany Steinbacher (1942) 1170 ~ ( Bird Sanctuary (Whipsnade) England Huxley (1936) 5800 2 Urban Arizona Emlen (1976) 1230 ­ - 4 1. ( Cottonwood Arizona Carothers and Johnson(1975a) 605.2 ­ 2. ~ I Arizona vegetation types after Brown and Lowe (1974). 3. ( 2 Density given in number of adult birds per 40 hectares (100 acres) instead of males or 4. 2 nest~g pairs (after Welty 1962). 5. ( 3 Average density for April and May, 'the height of breeding activity in the mesquite bosque. 6. ( 4 Riparian cottonwood habitat disturbed by urbanization. Two years prior, when the habitat 7. E was u~disturbed, the density was 1058.8 pairs/IOO acres. 8. S 5 Ohmart, R.D. and N. Stamp. No date. Final report on the field studies of the nongame 9. F birds-and small mammals of the proposed Orme Dam site. Bur. of Reel. Proj., Boulder City, 10. Y Ariz. 54 ms. p. II. V 12. E 13. E 14. (;

72 sand Table 3. -- Nesting birds of the Southwest Lowlands (Modified from Haight and Johnson 1977)1 iiliY !lted 15. Red-shafted Flicker Colaptes auratus cafer WETLANDS (2%) 16. Rose-throated Becard Platypsaris aglaiae 17. Tropical Kingbird Tyrannus melancholicus Clapper Rail Rallus longirostris 1. 18. Thick-billed Kingbird Tyrannus crassirostris Black Rail Laterallus jamaicensis 2. 19. Kiskadee Flycatcher Pitangus sulphuratus 3. American Recurvirostra americana 4. Snowy Plover Charadrius alexandrinus 20. Black Phoebe Sayornis nigricans 21. Willow Flycatcher Empidonax traillii WETLANDS AND OBLIGATE RIPARIAN (19%) 22. Western Wood Pewee Contopus sordidulus 23. Vermilion Flycatcher Pyrocephalus rubinus 1. Least Grebe Podiceps dominicus 24. Northern Beardless Flycatcher 2. Pied-billed Grebe Podilymbus podiceps Camptostoma imberbe 3. Double-crested Cormorant Phalacrocorax 25. Bank Swallow Riparia riparia auritus 26. Cliff Swallow Petrochelidon pyrrhonota 4. Olivaceous Cormorant Phalacrocorax olivaceus 27. Bridled Titmouse Parus wollweberi 5. Great Blue Heron Ardea herodias 28. White-breasted Nuthatch Sitta carolinensis 6. Green Heron Butor~striatus 29. Bewick's Thryomanes~ckii 7. Great Egret Casmerodius albus 30. American Robin Turdus migratorius 4 8. Snowy Egret Egreta thula----­ 31. Bell's Vireo Vireo bellii 2 9. Black-crowned Night Heron Nycticorax 32. Yellow-green Vireo Vireo flavoviridis 7 nycticorax 33. Tropical Parula Parula pitiayumi 3 Least Bittern Ixobrychus exilis 34. Yellow Warbler Dendroica petechia 6 Z 10. 11. Black-bellied Whistling-Du~ 35. Hooded Oriole Icterus cucullatus Dendrocygna autumnalis 36. Northern Oriole Icterus galbula 12. Mallard Anas platyrhynchos 37. Bronzed Cowbird Molothrus aeneus 13. Mexican Duck Anas diazi 38. Summer Tanager Piranga rubra 14. Gadwall Anas S"t"repera­ 39. Guiraca caerulea 15. Blue-winged Teal Anas discors 40. Painted Bunting ciris 16. Cinnamon Teal Ana~anoptera 41. White-collared Seedeater Sparophila torqueola 6 :l 17. Redhead Aythya americana 42. Lesser Goldfinch Carduelis psaltria 18. Ruddy Duck Oxyura jamaicensis 43. Albert's Towhee Pipilo aberti 19. Pandion haliaetus 20. Virginia Rail Rallus limicola PREFERENTIAL RIPARIAN (26%) 21. Sora Porzana c~a 22. Common Gallinule Gallinula chloropus 1. Peregrine Falcon Falco peregrinus 23. American Coot Fulica americana 2. Americ~n Kestrel Falco sparverius 24. Black-"necked Himantopus mexicanus 3. Gambel s Quail Lophortyx gambelii 25. Killrleer Charadrius vociferus 4. White-winged Dove Zenaida asiatica 26. Long-billed Marsh Wren Cistothorus palustris 5. Mourning Dove Zenaida macroura 27 Common Yellowthroat Geothlypis trichas 6. Common Ground Dove Columbina passerina 28. Yellow-breasted Chat Icteria virens 7. White-fronted Dove Leptotila verreauxi 29. Yellow-headed Blackbird -----­ 8. Greater Roadrunner Geococcyx californianus Xanthocephalus xanthocephalus 9. Groove-billed Ani Crotophaga sulcirostris 30. Red-winged Blackbird Agelaius phoeniceus 10. Barn Owl Tyto alba '6 31. Song Sparrow Melospiza melodia 11. Common Screech Owl Otus asio 12. Ferruginous Pygmy Ow~lauC:idium brasilianum OBLIGATE RIPARIAN (26%) 13. Lesser Nighthawk Chordeiles acutipennis 14. Black-chinned Hummingbird Archilochus alexandri 1. Common Merganser Mergus merganser 15. Anna's Hummingbird Calypte ~ 4 2. Mississippi Kite Ictinia mississippiensis 16. Gila Woodpecker Melanerpes uropygialis 3. Cooper's Hawk Accipiter cooperii 17. Golden-fronted Woodpecker Melanerpes aurifrons Ladder-backed Woodpecker Picoides scalaris I or 4. Zone-tailed Hawk Buteo albonotatus 18. 5. Gray Hawk Buteo n~s 19. Western Kingbird Tyrannus verticalis 6. Common Black Hawk Buteogallus anthracinus 20. Cassin's Kingbird Tyrannus vociferans 7. Bald Eagle Haliaeetus leucocephalus 21. Wied's Crested Flycatcher Myiarchus tyrannulus 8. Spotted Sandpiper Actitis macularia 22. Ash-throated Flycatcher Myiarchus cinerascens Rough-winged Swallow Stelgidopteryx ruficollis ~ame 9. Red-billed Pigeon Columba flavirostris 23. 10. Yellow-billed Cuckoo Coccyzus americanus 24. Green ~ 11. Violet-crowned Hummingbird Amazilia verticalis 25 . Common Raven corax 12. Buff-bellied Hummingbird Amazilia yucatanensis 26 • Verdin Auriparus-f1aVICeps 13. Broad-billed Hummingbird Cynanthus latirostris 27 . Northern Mockingbird Mimus polyglottos 14. Green Kingfisher Chloroceryle americana 28. LonR-billed ~toma longirostre

73 29. Curve-billed Thrasher curvirostre 9. Scaled Quail Callipepla squamata Ri 30. Crissal Thrasher Toxostoma dorsale 10. Great Horned Owl Bubo virginianus gr 31. Black-tailed Gnatcatcher Polioptila melanura 11. Elf Owl Micrathene whitneyi 10 32. Phainopepla Phainopepla nitens 12. Burrowing Owl Athene cunicularia 77 33. Common Starling Sturnus vulgaris 13. Long-eared Owl Asio otus rna 34. Lucy's Warbler Vermivora luciae 14. Poor-will Phalaenoptilus nuttallii Of 35. Lichtenstein's Oriole Icterus gularis 15. Pauraque Nyctidromus albicollis we 36. Brown-headed Cowbird Molothrus ater 16. White-throated Swift Aeronautes saxatalis COl 37. Cardinalis cardinalis 17. Lucifer Hummingbird Calothorax lucifer -­ On. 38. Pyrrhuloxia Cardinalis sinuata 18. Costa's Hummingbird Calypte costae bi] 39. Passerina cyanea 19. Gilded Flicker Colaptes auratus chrysoides we] 40. Lazuli Bunting Passerina ~ 20. Say's Phoebe Sayornis saya -- (nc 41. House Finch Carpodacus mexicanus 21. Horned Lark Eremophila alpestris COt

42. Olive Sparrow rufivirgatus 22. Purple Martin Progne subis ne~

43. Rufous-winged Sparrow Aimophila carpalis 23. White-necked Raven Corvus cryptoleucus',:" ne~ 24. Cactus Wren Campylorhynchus brunneicapillus 43 SUBURBAN AND AGRICULTURAL (4%) 25. Canyon Wren Catherpes mexicanus -- aff 26. Salpinctes obsoletus whi 1_ H1~rk Vultur~ Coragyps atratus 27. BBnoirB's ThrasnBr ToxosToma b2noir2i If 2Ji? 2. Rock Dove Columba livia 28. LeConte's Thrasher Toxostoma lecontei I Kin 3. Inca Dove Scardafella inca 29. Loggerhead Shrike Lanius ludovicianus hab 4. Barn Swallow Hirundo rustica 30. ~ella magna ave 5. House Sparrow Passer domesticus 31. Western Meadowlark neglecta dim 6. Great-tailed Grackle Quiscalus mexicanus 32. Scott's Oriole Icterus parisorum hab 33. Varied Bunting Passerina versicolor on NON-RIPARIAN (23%) 34. Brown Towhee Pipilo fuscus Gil 35. Grasshopper Sparrow Ammodramus S2vannarum (19 1. Turkey Vulture Cathartes aura 36. Lark Sparrow Chondestes grammacus Thr, 2. Red-tailed Hawk Buteo jam~nsis 37. Rufous-crowned Sparrow Aimophila ruficeps and 3. Swainson's Hawk Buteo swainsoni 38. Cassin's Sparrow Aimophila cassinii brei 4. Buteo regalis 39. Black-throated Sparrow Amphispiza bilineata morE 5. Harris' Hawk Parabuteo unicinctus that 6. Caracara Caracara cheriway dist 7. Prairie Falcon Falco mexicanus 166 Total breE 8. Common Bobwhite ~nus virginianus werE Six (Information from A.O.U. 1958, Bailey 1928, Bent-various dates, Hubbard 1970 and 1971, Johnson , the et al. 19732, Johnson et al.-manuscript3, Monson and Phillips 1964, Monson-personal communications, leas Oberholser 1974, Phillips et al. 1964, Rea 1977, Todd 1975 and undated, Wauer 1973, and Wolfe 1956) the 1 depa Haight, L.T. and R.R. Johnson. Paper presented at annual meeting of the Arizona Academy habi of Science, April 17, 1977. deve 2 Johnson, R.R., S.W. Carothers and D.B. Wertheimer, 1973. The importance of the Lower Gila and River, New Mexico, as a refuge for threatened wildlife. Unpubl. Rpt. to U.S. Fish and Wildl. the Serv' j Albuquerque. 53 p. Johnson, R.R., J.M. Simpson and J.R. Werner. Unpublished manuscript. Birds of the Salt River Valley, Maricopa Co., Arizona out when spec the spec: whicl habil

have of tl limit an at enanr: Othel: tion Rio Grande Valley. Habitats up through desert main populations are found in Mexico for a grasslands were considered, stopping at the large percentage of the birds that also occur lower edge of woodland and forests. 127 (or in the Southwest lowlands. Thus, it is 77%) of the 166 nesting species were in some argued, even complete loss of riparian and manner dependent on water related habitat. marshy habitat should cause no great problem Of this 77% dependent on water related habitat at the total population level for that species. well over half, 84 of the i66 species, are No argument could be further from the truth. xatalis completely dependent on water related habitat. The destruction of riparian habitat in northern Mexico is progressing at an alarming rate. ~ Only 39 species are non riparian nesting birds. Thus, if water dependent habitats One need but drive a few hundred miles south were completely destroyed in the Southwest from the United States-Mexico border to observe (not including suburban and agricultural) we the frantic rate at which Mexicans are draining could completely lose 47% of our lowland their streams and clearing riparian forests nesting birds while only 23% of our lowland and woodlands in an attempt to feed a rapidly nesting species would probably not be affected. expanding population. One reads with nostalgia 43 (26%) of the 166 species would be partially Sutton's book, "At a Bend in a Mexican River" affected. Granted, several of the species (1972). His accounts from travels in Mexico which are preferential riparian at lower only four decades ago tell of ferrying across rivers such as the Rio Purificacion and of lrei elevations, such as the Western and Cassin's Kingbirds, extensively use non riparian the lush growth in the Valley of the Rio ltei Corona. The riparian groves along these ,IUUS habitat at higher elevations. Still, the overall populations of these species would rivers are being cut at a rapid rate to make ~ diminish with the reduction or loss of riparian room for houses and fields. Rivers throughout ~ habitat at lower elevations. In a dissertation Mexico as well as the United States are being dammed to provide water for municipal and or on "Historic Changes in the Avifauna of the Gila Indian Reservation," near Phoenix, Rea industrial use and for large irrigation (1977) uncovered the following information. projects. Through the use of archaeological, ethnographic and historic sources he found that 101 species Thus, the same basic stages of "develop­ breed or have bred on the reservation with 5 ment of natural resources" which took place in more species that probably bred and 7 species the United States during two centuries promise that could have bred, based on biogeographic to occur in Mexico in a matter of decades. When distributions. During the past 100 years, 22 adding the available improved technology to breeding species were extirpated of which 18 Mexico's great wealth of natural resources, were related to the former riverine ecosystem. synergism may result. This may effect an even Six speices of non-nesting birds dependent on greater cummulative ecological disaster in a the Gila River, now dry, are also gone. At much shorter period of time than we have expe­ least 13 species have recently recolonized rienced in riverine ecosystems in the United the area as a result of reestablishment of a States. Thus, when evaluating the ecological depauparate form of the original riparian health of riparian species we must approach ~cademy habitat. This newly established habitat has the problem from the standpoint of a systems developed as a result of the use of the Salt analyst. One may start with his or her area ,wer and.Gila Rivers for disposal of effluent from of responsibility whether it be a few yards ldl. the Phoenix sewage treatment plants. of small stream or several hundred miles of a large river. However, we must be cognizant h.e Salt Others, e.g. Hubbard (1972) have pointed of the resources up and downstream from our out the lack of attention given to song birds area. We must show concern for the entire when designating threatened and endangered drainage system, even if primary responsibility species. However, to our knowledge, ours is for its management rests elsewhere. The the first attempt to quantify the number of managers of resource plots, cities, counties, species threatened or endangered by practices states, and countries need to recognize that which greatly modify or destroy riparian streams commonly flow thru lands in different habitat. ownership and across political boundaries.

Some proponents of water salvage projects have pointed out that many breeding species MANAGEMENT RECOMMENDATIONS of the Southwest lowlands are at the northern limits of their range. This, of course, is 1. The riparian habitat is the most productive an attempt to justify phreatophyte control, and possibly the most sensitive of North channelization, dam construction, grazing and American habitats and should be managed other practices w~ich reduce riparian vegeta­ accordingly. Due to the complexity of riverine tion and consequently riparian wildlife. The ecosystems, scientists have only recently

75 developed techniques to document the impor­ (c) Optimal as well as minimal require­ Bent, P. tance of these ecosystems to wildlife. ments for enhancing wildlife values Nort for a given habitat type. These in­ Yorl< 2. In addition to the importance of riparian clude ground cover, trees and shrubs Bull habitat from an ecological standpoint, other per hectare, foliage volume, plant values include: species present, and disturbance Boster, types and frequencies. cons (a) Recreational uses including hunting, vers fishing (Meehan et al. this symposium) We will close by quoting Carothers and in T and bird watching. Johnson (1975a), Asso (b) Reservoirs for preservation of gene pools and to allow recolonization of "Determining these factors may be Carothe areas hit by disasters such as the most important problem facing In p forest fires, severe droughts and us today. All the 'threatened Cany, storms. species recovery teams' we can alte (c) Aesthetic values including painting, possibly amass will not prevent Proc photography and just looking, listen­ many species from becoming extinct sear, ing, smelling, etc. in their native habitat if we de­ Park grade their habitats past the point Thus, recreational, wildlife, and aesthetic of no return." Carothel values should be weighed against other values summ;: and alternative uses. This is especially im­ surv~ portant in land use planning for a habitat LITERATURE CITED Watel which has high pressures from alternative uses Rive) such as water for industrial and domestic pur­ Allee, W.C., A.E. Emerson, O. Park, T. Park poses, irrigation, grazing and urbanization. and K.P. Schmidt. 1949. Principles of Carother animal ecology. W.B. Saunders, Philadel­ Aiter 3. Use interdisciplinary teams, including phia. xii + 837 p. and E recreation specialists, economists, etc., to ripar develop improved means for determining wildlife American Ornithologist's Union. 1957. Check­ values. This is especially important in figu­ list of North American birds. Fifth ed. Carother ring cost-benefit ratios for determining the A.O.U. Baltimore. xiii + 691 p. manag best use for an area. We hope there will nanga never be a need for putting a dollar figure on Arbib, R. 1976. The bluelist for 1977. Amer. 222. everything in order to establish its "value." Birds 30:1031-1039. Fares (What is the value of 2 or 3 days vacationing Birds along a streamside?) However, economic values Arizona Game and Fish Department. 1977. Memo No. 1 have been placed, in part, on recreation such concerning endangered and threatened species as hunting, fishing, and "general rural recrea­ in Arizona. Ariz. Game and Fish Dept., Carother tion" (Davis 1967, and Martin et al. 1974). Phoenix. 3 p. effec Attempts to quantify these values should make birds them more competitive with other uses, such as Arizona Water Commission. 1972. 16th Annual p. 60 those mentioned in No.2 (above). Arizona Watershed Symposium Proc. Ariz. Chann Water Comm. Rpt. 43 p. Servo 4. Finally, encourage investigations to Clary, W clarify areas of knowledge which are currently Bailey, F.M. 1928. Birds of New Mexico. N. poorly, if at all, known. We have discussed Mex. Dept. Game and Fish. Judd and junip' ducts the complexity of riverine ecosystems and Detweiler, Inc., Wash., D.C. xxiv + 807 p. further reasons for the late development of Res. J this area of ecology. Barr, G.W. 1956. Recovering rainfall, Part Range Arizona watershed program. Coop. Proj. Davis, W. Problems which need to be solved include: Ariz. State Land Dept., Water Div., Salt River Valley Water User's Assn., Univ. of fishir < (a) The minimum area and suitable config­ Ariz. 33 p. ness urations necessary to retain both Tempe. plant and wildlife values in dif­ Behnke, R.J. and M. Zarn. 1976. Biology and Deacon, ~ ferent riparian habitats. management of threatened and endangered western trouts. USDA For. Servo Tech. Rpt. fishes (b) The maximum distance which can sepa­ RM-28 , Rocky Mtn. For. and Range Exp. Sta., Acaden rate islands of a given habitat type Ft. Collins, Colo. 45 p. before the loss of wildlife species or a great reduction in populations occurs.

76 ~quire­ Bent, A.C. Various dates. Life histories of Dolan, R., B. Hayden, A. Howard and R.R. values North American birds. Dover Publ., New Johnson. In press. Man's impact on Colo­ lese in­ York. (Republication of U.S. Natl. Mus. rado River fluvial deposits within Grand :I shrubs Bulls. issued from 1919-1968). Canyon. In Proc. First Conference on plant Scientifi~Research in the National Parks. ince Boster, R.S. and L.R. Davis. 1972. Soil-loss USDI Natl. Park Serv., Wash., D.C. considerations in -to-grass con­ version, p. 243-250. In Proc. Watersheds Dolan, R., A. Howard and A. Gallenson. 1974. L1d in Transition Symp., Am. Water Resour. Man's impact on the Colorado River in the Assoc., Urbana, Ill. Grand Canyon. Amer. Sci. 62:392-401. e Carothers, S.W.,S.W. Aitchison and R.R. Johnson. Duisberg, P.C., Ed. 1957. Problems of the g In press. Natural resources in Grand upper Rio Grande: an arid zone river. Canyon National Park and river management Report of AAAS in coop. with UNESCO, D.S. alternatives on the Colorado River. In Comm. for Arid Resour. Improvement and Proc. First Conference on Scientific Re­ Development. Wash., D.C. 69 p. ct search in the National Parks. USDI Natl. Park Serv., Wash. D.C. Emory, W.T. 1858. Notes of military recon­ int naissance from Fort Leavenworth in Missouri Carothers, S.W. ~nd R.R. Johnson. 1971. A to San Diego in California. Wendell and summary of the Verde Valley breeding bird Van Benthvysen, Wash., D.C. 614 p. survey. Ariz. Game and Fish Dept. Land and Water Projects Investigations. Verde Ffolliott, P.F. and D.B. Thorud. 1974. Vege­ River Studies. Project FW-16-l0. 20 p. tation management for increased water yield Park in Arizona. Agr. Exp. Sta., Dniv. of Ariz., Carothers, S.W., R.R. Johnson and S.W. Tucson. iii + 38 p. ,s of Aitchison. 1974. Population structure .lade1­ and social organization of southwestern Fisher, J., N. Simon and J. Vincent. 1969. riparian birds. Amer. Zool. 14:97-108. Wildlife in danger. Viking press, New Check­ York. 368 p. Carothers, S.W. and R.R. Johnson. 1975a. Water :h ed. management practices and their effects on Friedman, H. 1929. The cowbirds. Thomas nongame birds in range habitats, p. 210­ Publ., Baltimore, Md. xv + 421 p. 222. In Proc. of S_vmP. on Mana,Jlemenr D.f Forest-and Range Habitats for Nongame Gaines, D. ~314. a new look at the nesting Birds. USDA For. Servo Gen. Tech. Rpt. riparian avifauna of the Sacramento Valley, No.1. Wash., D.C. C.~\:\.t~~\:e., ~'e't.\.'e"t.'-" "t':..:tCl.'i!.. ":::l~'i:i\-'?,\). Carothers, S.W. and R.R. Johnson. 1975b. The ,pt. , Greenway, J.C. 1958. Extinct and vanishing effects of stream channel modification on birds of the world. Amer. Comm. for Int. birds in the southwestern United States, Wildl. Protection, Spec. Pub. No. 13. p. 60~76. In Proc. of Symp. on Stream New York. 518 p. I Annual Channel Modification. USDI Fish and Wildl. Ariz. Serv., Off. BioI. Serv., Wash., D.C. Hibbert, A.R., E.A. Davis and D.G. Scholl. 1974. Chaparral conversion potential in Clary, W.P. et al. 1974. Effects of pinyon­ o. N. Arizona Part I: Water yield response and juniper removal on natural resource pro­ effects on other resources. USDA For. Servo ducts and uses in Arizona. USDA For. Servo + 807 p. Res. Paper RM-126. Rocky Mtn. For. and Res. Paper RM-128. Rocky Mtn. For. and Range Exp. Sta., Ft. Collins, Colo. 36 p. Range Exp. Sta., Flagstaff, Ariz. 28 p. , Part 'roj. Hickey, J.J., Ed. 1969. Peregrine Falcon pop­ Davis, W.C. 1967. Values of hunting and Salt ulations, their biology and decline. Dniv. fishing in Arizona in 1965. ColI. of Busi­ .iv. of of Wis. Press, Madison. xxii + 596 ~. ness and Public Adm., Ariz. State Univ., Tempe. vii + 91 p. Holden, C. 1977. Review of law triggered by ogy and Tellico impasse. Sci. 196:1426-1428. Deacon, J.E• .ana ltJ.L. Nin.ck1ey. .19/4<. Z)e$erc ,cred ch. Rpt. fishes, p. 385-488. In Desert Biology. Holden, P.B. and C.B.Sta1naker. 1975. Distri­ p. Sta., Academic Press, New York. bution and abundance of mainstream fishes of the middle and upper Colorado River basins, 1967-1973. Trans. of the Amer. Fisheries Soc. 104(2):217-231.

77 Horton, J.S. and C.J. Campbell. 1974. Minckley, W.L. 1973. Fishes of Arizona. Ariz. prince Ph ill Management of phreatophyte and riparian Game and Fish Dept., Phoenix. xvi + 293 p. crisis. I vegetation for maximum multiple use values. Co., Inc. USDA For. Servo Res. Paper RM-117. Rocky Minckley, C.O. and D.W. Blinn. 1976. Summer and New y, Mtn. For. and Range Exp. Sta., Ft. Collins, distribution and reproductive status of fish Colo. 23 p. of the Colorado River in Grand Canyon Rea, A.M. 19 National Park and vicinity .during 1975-76. fauna of Hubbard, J.P. 1970. Checklist of the birds Colo. R. Res. Tech. Rpt. No. 14, USDI Natl. Central A of New Mexico. New Mexico Ornith. Soc. Park Serv., Grand Canyon Natl. Park. 17 p. Univ. of . Publ. No.3. McLeod Printing Co., Albuquerque. 108 p. Minckley, W.L. and J.E. Deacon. 1968. South­ schorger, A.I western fishes and the enigma of "endangered its natur. Hubbard, J.P. 1971. The summer birds of the species." Sci. 159:1424-1432. of Wiscon Gila Valley, New Mexico. Nemouria, Occas. Papers of the Delaware Mus. Nat. His. 2:1-35. Monson, G. and A.R. Phillips. 1964. Species Sigler, W.F. of birds in Arizona. In The Vertebrates . Ut, Hubbard, J.P. 1972. Southwestern , of Arizona. Univ. of Ariz. Press, Tucson. Lake City p. 79-96. In Proc. of Symp. on Rare and 270 p. Endangered Wildlife of the Southwestern Simon, N, an, United States. New Mexico Game and Fish National Audubon Society. 1975. The seventy­ vors: the Dept., Santa Fe. 167 p. fifth Christmas bird count. Amer. Birds danager 0 29(2):151-638. New York. Hubbard, J.P. 1977. A biological inventory of the Lower Gila River Valley, New Mexico. New Mexico Game and Fish Dept. 1972. Proc. Stevens, L.E New Mexico Dept. Game and Fish, 56 p. of the Symp. on rare and endangered wild­ Grand Can: life of the southwestern United States. cal surve: Johnson, R.R. 1970. Tree removal along New Mexico Game and Fish Dept., Santa Fe. Colorado: southwestern rivers and effects on associated 167 p. Wash CHf organisms. Amer. Phil. Soc., Yearb. 1970. 10, USDI I p. 321-322. Oberholser, H.C. 1974. Bird life of Texas, Natl. Pari E.B. Kincaid, Jr., ed., Vol. I and II. Johnson, R.R. 1977. Synthesis and management Univ. of Texas Press, Austin. 1069 p. Suttkus, R.D implications of the Colorado River research C. R. Shoo' program. Colo. R. Res. Tech. Rpt. No. 17. O'Brien, J. 1976. Observations on furbearers mammals a1 USDI Natl. Park Serv., Grand Canyon Natl. within the riparian habitat of the upper River in I Park. 50 ms. p. Sacramento River. Calif. Dept. Fish and Rpt. No. Game Memo Rpt. iii + 12 p. Canyon Na Johnson, R.R. and S.P. Martin. 1976. The Colorado River research project: a National Odum, E. 1959. Fundamentals of ecology. W.B. Sutton, G.M. Park Service multidisciplinary, interdisci­ Saunders Co., Philadelphia. xvii + 546 p. river. Pi plinary research project, p. 29-41. In xvii + 12, Proc. of the 3rd Resources Management-Conf. Pettingill, G.S. 1970. in USDI Natl. Park Serv., Wash., D.C. laboratory and field. Burgess Publ. Co., Thompson, R.: Minneapolis. xvii + 524 p. managemen Laursen, E.M. and E. Silverston. 1976. Hydro­ USDI Burei logy and sedimentology of the Colorado Phillips, A.R. 1968. The instability of the Tall Timb, River in Grand Canyon. Colo. R. Res. distribution of land birds in the Southwest, 11 + 188 I Tech. Rpt. No. 13, USDI Natl. Park Serv., p. l29-l62~ In Collected Papers in Honor Grand Canyon Natl. Park. 27 p. of Lyndon Lane Hargrave, Papers of the Todd, R.L. Arch. Soc. of N. Mex.: 1. Mus. of New birds. A Lowe, C.H., Ed. 1964. The vertebrates of Mexico. Press, Santa Fe. v + 170 p. W-53-R-26 Arizona. Univ. of Ariz. Press, Tucson, 270 p. Phillips, A., J. Marshall and G. Monson. Todd, R.L. 1964. The birds of Arizona. Univ. of mammals o. Martin, W.E., R.L. Gum and A.H. Smith. 1974. Ariz. Press, Tucson. xviii + 212 p. prising tl The demand for and value of hunting, fishing, Arizona. and general rural outdoor recreation in Powell, J.W. 1961. The exploration of the Rpt. W-53­ Arizona. Agr. Exp. Sta., Ariz. State Univ., Colorado River and its . Dover Tempe. ix + 56 p. Publ., Inc., New York. xiv + 397 p. Tylinek, r. (Unabridged republication of work publ. species. Miller, A.H. 1951. An analysis of the distri­ in 1895 by Flood and Vincent, Canyons of 284 p. bution of the birds of California. Univ. of the Colorado). Cal. Publ. Zool. 50:531-643.

78 Ariz. Prince Phillip and J. Fisher. 1970. Wildlife U.S. Fish and Wildlife Service. 1968. Rare 13 p. crisis. Hamish Hamilton Ltd., Cowles Book and endangered fish and wildlife of the Co., Inc., and World Wildlife Fund., Chicago United States. USDI Fish and Wildl. Serv., nner and New York. 256 p. Bur. of Sport Fisheries and Wildl., Wash., : fish D.C. xi + 171 p. Rea, A.M. 1977. Historic changes in the avi­ ·76. fauna of the Gila River Indian Reservation, U.S. Fish and Wildlife Service. 1973. ~atl. Central Arizona. Doctoral Dissertation, Threatened wildlife of the United States. 7 p. Univ. of Ariz., Tucson. ~iii + 346 p. USDI Fish and Wildl. Serv., Bur. of Sport Fisheries and Wildl., Office of End. )Uth- Schorger, A.W. 1955. The passenger pigeon: Species and Int. Activities, Wash., D.C. 1gered its natural history and extinction. Univ. xiii + 289 p. of Wisconsin Press, Madison. xiii + 424 p. U.S. Fish and Wildlife Service. 1976. The Southern Bald Eagle in Arizona: a status :ies Sigler, W.F. and R.R. Miller. 1963. Fishes of report. End. Species Rpt. No.1. USDI Utah. Utah Dept. of Fish and Game, Salt Fish and Wildl. Serv., Div. of Wildl. ;on. Lake City. 203 p. Serv., Phoenix, Az. 33 p. Simon, N. and P. Geroudet. 1970. Last survi­ U.S. Forest Service. 1975. Endangered and 1!nty­ vors: the natural history of animals in unique fish and wildlife of the southwestern is danager of extinction. World Publ. Co., national forests. USDA For.Serv. Wildl. New York. 275 p. Habitat Manag. Staff Group, Albuquerque, N. Mex. viii + 203 p. c. Stevens, L.E. 1976. An insect inventory of ld- U.S. National Park Service. 1974. Threatened Grand Canyon, p. 123-128. In An ecologi­ wildlife in the Western Region of the cal survey of the riparian zone of the National Park Service. USDI Natl. Park ~e. Colorado River between Lees Ferry and Grand Servo West. Reg. Office, San Francisco. Wash Cliffs. Colo. R. Res. Tech. Rpt. No. vi + 68 p. 10, USDI Natl. Park Serv., Grand Canyon s, Natl. Park. 251 p. Van Tyne, J. and A.J. Berger. 1971. Fundamentals of ornithology. Dover Publ., Suttkus, R.D., G.H. Clemmer, C. Jones and Inc., New York. xi + 624 p. C.R. Shoop. 1976. Survey of fishes, Warnock, B.H. and J.L. Gardner, Ed. 1960. rers mammals and herpetofauna of the Colorado Water yield in relation to environment in er River in Grand Canyon. Colo. R. Res. Tech. the southwestern United States. In Proc. ad Rpt. No.5. USDI Natl. Park Serv., Grand of Symp. SWARM Section AAAS, SuI Ross St. Canyon Natl. Park. 48 p. ColI, Alpine, Texas. 74 p. W.B. Sutton, G.M. 1972. At a bend in a Mexican Wauer, R.W. 1973. Birds of Big Bend National 5 p. river. Paul Eriksson, Inc., New York. Park and vil,inity. Big Bend Nat. Rist. xvii + 124 p. Assn. xv + 223 p. Welty, J.e. 1975. The life of birds. Second o. , Thompson, R.L., Ed.197l. The ecology and management of the Red-cockaded Woodpecker. ed. W.B. Saunders, Philadelphia. xv + 623 p. USDI Bureau of Sport Fisheries and Wildlife, the Tall Timbers Res. Sta., Tallahassee, Fla. Wolfe, L.R. 1956. Checklist of the birds of hwest, ii + 188 p. Texas. Intelligencer Print. Co., Lancaster, nor Pa. 89 p. Todd, R.L. No date. Field checklist of Arizona birds. Ariz. Game and Fish Dept. Proj. Woodbury, A.M. et al. 1959. Ecological studies W-53-R-26. 4 p. of the flora and fauna in Glen Canyon. Univ. of Utah Anthro. Papers (Glen Canyon Series Todd, R.L. 1975. The species of birds and No.7), Oniv. of Utah Press, Salt Lake City. 226 p. mammals occurring on the watersheds com­ prising the Colorado River drainage of Zimmerman, D.R. 1976. Endangered bird species: Arizona. Ariz. Game and Fish Dept. Spec. habitat manipulation methods. Sci. e Rpt. W-53-R-26. 53 p. 192:876-878,

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79