Skip to main content
Log in

Passive recovery of an island bird community after rodent eradication

  • Original Paper
  • Published:
Biological Invasions Aims and scope Submit manuscript


The number and scale of island invasive species eradications is growing, but quantitative evidence of the conservation efficacy of passive recovery is limited. We compare relative abundances of breeding birds on Hawadax Island (formerly named Rat island), Aleutian Archipelago, Alaska, pre- and post- rat eradication to examine short-term (<1 year post-eradication) changes due to rodenticide application, and medium-term (5 years post-eradication) changes due to the absence of invasive rats. In the short term, Bald Eagle (Haliaeetus leucocephalus) numbers decreased from 24 individuals pre-eradication to two individuals <1 year post-eradication, but recovered to 10 individuals (42 % of pre-eradication) 5 years post-eradication, with all individuals nesting (63 % of the pre-eradication nesting). Five years post-eradication relative abundances of most terrestrial birds surveyed using point counts either significantly increased [Gray-crowned Rosy Finch (Leucosticte tephrocotis), Lapland Longspur (Calcarius lapponicus), Snow Bunting (Plectrophenax nivalis), Song Sparrow (Melospiza melodia)] or did not differ [Pacific Wren (Troglodytes troglodytes)]. Shorebirds also increased 5 years post-eradication with Black Oystercatchers (Haematopus palliates) increasing fivefold, and Rock Sandpiper (Calidris ptilocnemis) nesting increasing from one to five nests. We confirmed two species of ground nesting seabirds [Tufted Puffin (Fratercula cirrhata) and Leach’s Storm-petrel (Oceanodroma leucohoa)] as nesting (puffin) or engaged in courtship behavior (Storm-petrel) 5 years post-eradication. Our results indicate that despite the short-term impact on Bald Eagles, and without further human intervention, most terrestrial and marine birds have newly-colonized, re-colonized, or increased in abundance following the eradication of invasive rats.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4

Similar content being viewed by others


  • Anthony RG, Estes JA, Ricca MA, Miles AK, Forsman ED (2008) Bald eagles and sea otters in the Aleutian Archipelago: indirect effects of trophic cascades. Ecology 89:2725–2735

    Article  PubMed  Google Scholar 

  • Bailey E (1993) Introduction of Foxes to Alaskan Islands—history, effects on avifauna, and eradication. US Fish and Wildlife Service Resource Publication, Washington

    Google Scholar 

  • Bellingham PJ, Towns DR, Cameron EK, Davis JJ, Wardle DA, Wilmshurst JM, Mulder CPH (2010) Feathers to fur New Zealand island restoration: seabirds, predators, and the importance of history. N Z J Ecol 34:115–136

    Google Scholar 

  • Borker AL, McKown MW, Ackerman JT, Eagles-Smith CA, Tershy BR, Croll DA (2014) Vocal activity as a low cost and scalable index of seabird colony size. Conserv Biol 28:1100–1108

    Article  PubMed  Google Scholar 

  • Buckelew S, Howald G, MacLean S, Byrd V, Daniel L, Ebbert S, Meeks W (2008) Rat Island habitat restoration project: operational report. Report to USFWS. Island Conservation, Santa Cruz

  • Buckelew S, Byrd V, Howald G, MacLean S, Sheppard J (2011) Preliminary ecosystem response following invasive Norway rat eradication on Rat Island, Aleutian Islands, Alaska. In: Veitch CR, Clout MN, Towns DR (eds) Island invasives: eradication and management. International Union for the Conservation of Nature, Gland, pp 275–279

    Google Scholar 

  • Buxton RT, Major HL, Jones IL, Williams JC (2013) Examining patterns in nocturnal seabird activity and recovery across the Western Aleutian Islands, Alaska, using automated acoustic recording. Auk 130:331–341

    Article  Google Scholar 

  • Byrd GV, Renner HM, Renner M (2005) Distribution patterns and population trends of breeding seabirds in the Aleutian Islands. Fish Oceanogr 14:139–159

    Article  Google Scholar 

  • Clavero M, Brotons L, Pons P, Sol D (2009) Prominent role of invasive species in avian biodiversity loss. Biol Conserv 142:2043–2049

    Article  Google Scholar 

  • Croll DA, Maron JL, Estes JA, Danner EM, Byrd GV (2005) Introduced predators transform subarctic islands from grassland to tundra. Science 307:1959–1961

    Article  CAS  PubMed  Google Scholar 

  • DIISE (2015) The database of island invasive species eradications. Developed by Island Conservation, Coastal Conservation Action Laboratory UCSC, IUCN SSC Invasive Species Specialist Group, University of Auckland and Landcare Research New Zealand. Accessed 20 Oct 2015

  • Donlan CJ, Howald GR, Tershy BR, Croll DA (2003) Evaluating alternative rodenticides for island conservation: roof rat eradication from the San Jorge Islands, Mexico. Biol Conserv 114:29–34

    Article  Google Scholar 

  • Ebbert SE, Byrd GV (2002) Eradications of invasive species to restore natural biological diversity on Alaska Maritime National Wildlife Refuge. In: Veitch CR, Clout MN, Towns DR (eds) Island Invasives: eradication and management. International Union for the Conservation of Nature, Gland, Switzerland, pp 102–109

    Google Scholar 

  • Elzinga CL, Salzer DW, Willoughby JW, Gibbs JP (2001) Measuring and monitoring plant and animal populations. Blackwell Science Inc, Malden

    Google Scholar 

  • ESRI (Environmental Systems Research Institute) (2013) ArcMap version 10.2. ESRI, Redlands, California

  • Funk C (2012) Rat Islands archaeological research 2003 and 2009: working toward an understanding of regional cultural, and environmental histories. Arctic Anthropol 48:25–51

    Article  Google Scholar 

  • Gibson DD, Byrd GV (2007) Birds of the Aleutian Islands. Nuttal Ornithological Club, American Ornighologists’ Union, Cambridge

    Google Scholar 

  • Howald GR, Mineau P, Elliott JE, Cheng KM (2000) Brodifacoum poisoning of avian scavengers during rat control on a seabird colony. Ecotoxicology 8:431–447

    Article  Google Scholar 

  • Howald G, Donlan CJ, Galvan JP, Russell JC, Parkes J, Samaniego A, Wang Y, Veitch D, Genovesi P, Pascal M, Saunders A, Tershy B (2007) Invasive rodent eradication on islands. Conserv Biol 21:1258–1268

    Article  PubMed  Google Scholar 

  • Howald G, Donlan CJ, Faulkner KR, Ortega S, Gellerman H, Croll DA, Tershy BR (2009) Eradication of black rats Rattus rattus from Anacapa Island. Oryx 44:30–40

    Article  Google Scholar 

  • Jones H (2010) Seabird islands take mere decades to recover following rat eradication. Ecol Appl 20:2075–2080

    Article  PubMed  Google Scholar 

  • Jones HP, Tershy BR, Zavaleta ES, Croll DA, Keitt BS, Finkelstein ME, Howald GR (2008) Severity of the effects of invasive rats on seabirds: a global review. Conserv Biol 22:16–26

    Article  PubMed  Google Scholar 

  • Kappes PJ, Jones HP (2014) Integrating seabird restoration and mammal eradication programs on islands to maximize conservation gains. Biodivers Conserv 23:503–509

    Article  Google Scholar 

  • Keitt B, Campbell K, Saunders A, Clout M, Wang Y, Heinz R, Newton K, Tershy B (2011) The Global Islands Invasive Vertebrate Eradication Database: a tool to improve and facilitate restoration of island ecosystems. In: Veitch DR, Clout MN, Towns DR (eds) Island invasives: eradication and management. Internation Union for the Conservation of Nature, Gland, pp 74–77

    Google Scholar 

  • Kurle CM, Croll DA, Tershy BR (2008) Introduced rats indirectly change marine rocky intertidal communities from algae- to invertebrate-dominated. Proc Natl Acad Sci USA 105:3800–3804

    Article  PubMed Central  CAS  PubMed  Google Scholar 

  • Lavers JL, Wilcox C, Donlan CJ (2010) Bird demographic responses to predator removal programs. Biol Invasions 12:3839–3859

    Article  Google Scholar 

  • Loehle C, Eschenbach W (2012) Historical bird and terrestrial mammal extinction rates and causes. Divers Distrib 18:84–91

    Article  Google Scholar 

  • Lorvelec O, Pascal M (2005) French attempts to eradicate non-indigenous mammals and their consequences for native biota. Biol Invasions 7:135–140

    Article  Google Scholar 

  • Major HL, Jones IL, Byrd GV, Williams JC (2006) Assessing the effects of introduced Norway rats (Rattus norvegicus) on survival and productivity of Least Auklets (Aethia pusilla). Auk 123:681–694

    Article  Google Scholar 

  • Maron JL, Estes J, Croll DA, Danner EM, Elmendorf SC, Buckelew SL (2006) An introduced predator alters Aleutian Island plant communities by thwarting nutrient subsidies. Ecol Monogr 76:3–24

    Article  Google Scholar 

  • Paul E, Salmon T (2010) The Rat Island eradication project: a critical evaluation of nontarget mortality. The Ornithological Council, Bethesda

    Google Scholar 

  • Russell JC (2011) Indirect effects of introduced predators on seabird islands. In: Mulder CP, Anderson WP, Towns DR, Bellingham PJ (eds) Seabird islands ecology, invasion, and restoration. Oxford University Press, New York, pp 261–279

    Chapter  Google Scholar 

  • Tershy BR, Shen KW, Newton KM, Holmes ND, Croll DA (2015) The importance of islands for the protection of biological and linguistic diversity. Bioscience 65:592–597

    Article  Google Scholar 

  • Towns DR (2008) Eradications as reverse invasions: lessons from Pacific rat (Rattus exulans) removals on New Zealand islands. Biol Invasions 11:1719–1733

    Article  Google Scholar 

  • Towns DR, Atkinson IAE, Daugherty CH (2006) Have the harmful effects of introduced rats on islands been exaggerated? Biol Invasions 8:863–891

    Article  Google Scholar 

  • Towns DR, Byrd GV, Jones HP, Rauzon MJ, Russell JC, Wilcox C (2011) Impacts of introduced predators on seabirds. In: Mulder CP, Anderson WP, Towns DR, Bellingham PJ (eds) Seabird islands ecology, invasion, and restoration. Oxford University Press, New York, pp 56–90

    Chapter  Google Scholar 

  • US Board on Geographic Names (2012) Geographic Names Post Phase I Board/Staff Revisions. 10 May 2012

  • US Fish and Wildlife Service (2007) Restoring wildlife habitat on Rat Island environmental assessment. Alaska Maritime National Wildlife Refuge, Aleutian Islands Unit, Alaska

    Google Scholar 

Download references


We gratefully acknowledge field assistance provided by S. Abel, E. Bishop, A. Chateau, K. Cunningham, R. Dingler, S. Ebbert, C. Eggelston, R. Federer, J. Giffard, C. Hanson, R. Heinz, J. Helm, E. McCreless, A. McInturff, M. Mumm, K. Outten, R. Shaening-Pokrasso, and R. Stansbury. Alaska Maritime National Wildlife Refuge Staff, particularly V. Byrd, A. Sowls, S. Ebbert, G. Siekaniec and the crew of the R/V Tiglax provided invaluable research support. We were supported in part by the National Science Foundation (OPP-9985814), the National Fish and Wildlife Foundation (0101.12.030733) and the David and Lucile Packard Foundation. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the National Fish and Wildlife Foundation. Mention of trade names or commercial products does not constitute their endorsement by the National Fish and Wildlife Foundation.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Donald A. Croll.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Croll, D.A., Newton, K.M., McKown, M. et al. Passive recovery of an island bird community after rodent eradication. Biol Invasions 18, 703–715 (2016).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: