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

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 Gray: extant forest Black: destroyed p. 642

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

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 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 Fire Ants: 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

51. Cowbird Removal: Successes Golden-cheeked Warbler: rate of parasitized nests down from 90% in 1987 to 22% in 1996. Black-capped Vireo: rate of parasitized nests down from 90% in 1987 to 40%. SW Willow Flycatcher: rate of parasitized nests down from 63% in 1989-1991 to 15% in 2003, nest success increased from 20 to 61%.

52. Cowbird Removal: Mixed Results Least Bell’s Vireo: populations increased following cowbird control and efforts to improve habitat Kirtland’s Warbler: cowbird control and habitat restoration increased population from 200 breeding pairs in 1972 to 1800 breeding pairs in 2007. SW Willow Flycatcher: After 12 years of cowbird control CA pop. still decreased. Suggests that habitat, not cowbirds, is limiting factor.

53. Cowbirds and Conservation What to do about it? Habitat issues are primary concerns –Increase nesting habitat for songbirds –Decrease habitat fragmentation that favors cowbirds Cowbird Control = not a long-term solution –May help very small populations increase to reestablish a stable breeding population, but don’t promote long-term recovery