Birds & Conservation

1. Birds & Conservation A Global & Local Perspective

2. Major Conservation Issues • Humans • Habitat • Toxic compounds • Exotic species • Island Effect • Nest Parasites

3. General Effects of Humans:we take up space & demand resources • Human population & associated effects • Huge size (~ 6 billion) • Future increases in population - some models suggest peaks @ between 12-20 billion • Development (all ↓ available habitat) • Housing • Industry • Agricultural

4. Human Presence

6. Other Associated Human Effects • Excessive Hunting • when going beyond sustainable levels • turn of century feather collectors • poaching of endangered species • Examples: • Passenger Pigeon • Great Auk • Eskimo Curlew & other shorebirds

7. Once the most abundant bird in North America, the Passenger Pigeon is now extinct. Overhunting for markets is though to be one contributing factor.

8. Formerly a common spring migrant in in eastern SD; now probably extinct Eskimo Curlew Texas 1962

9. Upcoming Schedule • Final Field Trip – Sat., May 1 • Newton Hills State Park • 0730-1400 • Final Exam • Thursday, May 6 • 1230 to 1430 • Will cover material since second exam (Social Systems through Conservation)

10. Other Associated Human Effects…… • Road Kills • Cats • Collisions • buildings, windows, communications towers • Human activities directly kill an estimated 1 billion birds each year in the U.S.

11. Avian Collision Study (Erickson et al.2005)Annual estimates of U.S. Mortality • Vehicles (80 million) • Buildings/Windows (100 million-1 billion) • Powerlines (130 million) • Communication Towers (4-5 million) • Wind Turbines (20-40 thousand) • For comparison: house cats = about 100 million annually in N. America • Total anthropogenic mortality = > 1 billion

12. Habitat Destruction • Loss • destroyed altogether • removal and replacement with human-altered habitat • Fragmentation • partial destruction as well as separation of once-connected areas into isolated fragments • leads to lower total area & possible separation of populations in fragments

13. Habitat Destruction…… • Degradation • lower quality due to a variety of factors such as exotic species, increased edge, toxins, etc. • cheatgrass or other weeds • agricultural runoff in a stream

15. Many habitats are threatened • Tropical Rainforests • Temperate Forests • Wetlands/Riparian Areas • Grasslands • With loss of habitat, there is less area to sustain populations

16. New World Rainforest p. 642 Gray: extant forest Black: destroyed

17. SE Asian Rainforest p. 642 Gray: extant forest Black: destroyed

18. Examples • Golden-cheeked Warbler • breeds central Texas • winters S Mexico • housing developments, recreation, etc. • cowbirds • Riparian birds in South Dakota • many woodland habitats now gone due to dams and conversion to agriculture • limited habitat area for populations

19. Note dramatic decreases in forest and grassland habitats

20. Migratory Birds • Need suitable habitat for all phases of life cycle: • breeding, wintering, migration • Habitats migrants use often differs among seasons • Conservation plans must be complex to safeguard all important habitats

21. Habitat Conservation Efforts • Preserves: • National Parks, National Wildlife Refuges, National Forests & Grasslands, state & local parks, private • Conservation easements: • private land set aside, CRP • Endangered Species Act: • mandates protection for species threatened by human activities • Need ecosystem-based approaches

22. Environmental toxins • Pesticides • DDT • PCB’s • Fertilizers • Fossil Fuels • Household Chemicals

23. Pesticides • Widespread use: • household & lawns • agricultural • pest control • Many effects • reduce prey populations • non-target mortalities • For example, Birds of Prey • bio-accumulation and bio-magnification

24. Example of Pesticide Effects: DDT • DDT: 1,1,1-trichloro-2,2-bis-(p-chlorophenyl) ethane • widespread use mid-1900s • population declines noticed in many birds, especially predators • Osprey, Bald Eagle, Peregrine Falcon • Peregrine almost extinct in eastern US • DDT banned in US in 1972 • subsequent rebound of all raptor species affected

25. Bald Eagles before & after DDT ban: Reproduction & amounts of DDE p. 565

26. Local Toxin Example: Selenium & colonial waterbirds • Selenium (Se): • trace mineral • important in small amounts • key component of enzymes

27. Selenium & colonial waterbirds • The problem: • high concentrations of Se found in some soil types: (e.g., marine shale) • Se leaches from soil in high amounts • agricultural run-off leads to high [ ] in bodies of water • Se will bioaccumulate (increasing levels as you move up food chain)

28. Selenium & colonial waterbirds • Effects on birds: • deformities • reduced reproductive success • Rookery @ Stratford Slough (Brown Co., SD) • ~ 1000 birds ‘destroyed’ due to selenium

29. Exotic Species

30. Exotic Species • Exotic Introduced Non-native • any species living outside of its natural range • Sources: • human colonists (“acclimatization societies”) • agriculture • accidental transport • biological control • ‘just for fun’

31. Examples of Exotic Species • southern US: Fire Ants • Guam: Brown Tree Snake • US: European Starling • House Sparrow • Rock Pigeon • Ring-necked Pheasants • Hawaii: > 50 introduced bird species

32. Why are exotics a problem? • Freedom from usual population limitation • no natural predators • no usual diseases • Competition with or predation of native species: • native species may have not evolved defenses or necessary behaviors to ‘deal with’ exotics

33. Effects of FireAnts: predation competition

34. Brown Tree Snake in Guam Bird

35. Exotic Birds • European Starling: • introduced to Central Park in NYC ~ 1890 • now most common bird in US • competes for food & nest cavities • House Sparrow & Rock Pigeon • more confined to human areas • still compete w/ natives • House Sparrow vs. Purple Martin

36. More Exotic Birds • Ring-necked Pheasant & other game birds (Chukar, Gray Partridge, etc.) • favored for hunting • may compete w/ native grouse (???)

37. Birds and Islands

38. Island Biogeography • ‘The small island effect’ • Small islands support small populations • Island populations often not exposed to full range of ecological factors • predators • pathogens

39. Island Biogeography…… • Evolve unique adaptations, which often lead to speciation • flightlessness • ground-nesting • More sensitive to changes in environment • Hawaii • Guam • fragmented habitats

40. Hawaii • Isolated volcanic islands • populated by founder species that colonized • adaptive radiation • many unique, locally adapted species • flightless Ibis & honeycreepers • few predators

43. Hawaii…… Human effects over last 2 millenia: • introduced pigs & other ungulates • over-grazing/browsing • introduced rats (nocturnal) • predators of many unsuspecting birds • introduced mongoose (diurnal) • preys on many birds (not rats!) • introduced mosquitoes • avian malaria w/ introduced birds • spread by mosquitoes

44. Hawaii…… • ~ 1/2 of original species remain • many remaining are threatened by habitat loss, diseases, & vagaries of small population size

45. Guam • Brown Tree Snake • elimination of all wild populations of Guam’s endemic birds: • rail, kingfisher, songbirds, etc.

46. Island Biogeography & Mainland Ecosystems • Naturally occurring ‘islands of habitat’: • Black Hills • ‘Sky Islands’ of desert southwest • Human-caused fragmentation: • once extensive areas now only patches • forest • grassland • etc.

48. Cowbirds and Conservation • Brood parasitism has negative impacts on host reproductive success • Cowbirds feed in open areas but parasitize many forest-dwelling songbirds • Human activities have allowed cowbirds to expand their range • Forest fragmentation  more open areas • Cattle ranching  associate with bison/cattle

49. Cowbirds and Conservation • Brown-headed Cowbirds have parasitized over 220 species • Of these < 25 eject cowbird eggs, 37 desert nest to renest, only a few build a new floor over clutch. Most are susceptible. • Parasitism probably not responsible for continent-wide population declines, but do impact some endangered species. • Least Bell’s Vireo, Kirtland’s Warbler, Black-capped Vireo, SW Willow Flycatcher)

50. Cowbirds and Conservation • Control Issues: • Some view killing cowbirds as inhumane • Cowbird removal is only a short-term solution to the problem • Cowbird removal is expensive • Bell’s Vireo: over $665K/year (225 traps/yr, each trap gets about 3,000 cowbirds/yr) • Kirtland’s Warbler: $90K/yr • Black-capped Vireo: $45K/yr • Removal doesn’t increase population size for all species