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Vertical segregation by breeding ring-necked parakeets Psittacula krameri in northern Italy


Cavities represent a limiting resource for breeding birds, thus triggering potential competition, mostly in urban ecosystems. The ring-necked parakeet Psittacula krameri is one of the main alien invasive bird species of the world. Introduced populations are reported for over 35 countries, Italy included. This parakeet mainly depends on trunk cavities for reproduction but, occasionally, it may nest within building holes. A growing population of this species is present in the urban area of Pavia (northern Italy). Differently, from what has been observed in other colonies of the global introduced range, most of this urban population nests within the putlog holes of the Visconti castle and surrounding towers, together with four native species. In this work, we counted the breeding pairs of ring-necked parakeets nesting within putlog holes of castle and tower walls and estimated the breeding population size. Observations were carried out once a week, 30 min before sunset, for an hour, from the start of April to the end of August 2016 and 2017. We assessed whether a vertical segregation occurred between parakeets and native species (i.e. the rock pigeon, the jackdaw, the Italian sparrow and the common swift) through a dissimilarity index. Inter-specific interactions have never been observed, despite two pigeon ticks being detected on rescued parakeets. A strong vertical segregation was observed between ring-necked parakeets and pigeons, and between ring-necked parakeets and common swifts. Ring-necked parakeets and jackdaws were mostly observed in the highest putlog holes. No breeding parakeet pair was observed within plain trunk cavities in the surroundings of the castle walls, which were instead occupied by jackdaws and tawny owls. Most parakeet nests were located on the eastern wall, where they receive the first light at dawn.

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  1. Alcock J (2009) Animal behavior: an evolutionary approach. Sinauer Associates (Eds.) Sunderland, Massachusetts, USA

  2. Bernini F, Dinetti M, Gariboldi A, Matessi G, Rognoni G (1998) Atlante degli uccelli nidificanti a Pavia. BirdLife & Lega Italiana Protezione Uccelli (Eds), Milano, Italy

  3. Bertolino S, Genovesi P (2003) Spread and attempted eradication of the grey squirrel (Sciurus carolinensis) in Italy, and consequences for the red squirrel (Sciurus vulgaris) in Eurasia. Biol Conserv 109:351–358

  4. Bertolino S, Cordero di Montezemolo N, Preatoni DG, Wauters LA, Martinoli A (2014) A grey future for Europe: Sciurus carolinensis is replacing native red squirrels in Italy. Biol Invasions 16:53–62

  5. Bonesi L, Palazon S (2007) The American mink in Europe: status, impacts, and control. Biol Conserv 134:470–483

  6. Bremner A, Park K (2007) Public attitudes to the management of invasive non-native species in Scotland. Biol Conserv 139:306–314

  7. Brichetti P, Caffi M, Gandini S (1992) Biologia riproduttiva di una popolazione di passera d’Italia, Passer italiae, nidificante in una colombaia della Pianura Lombarda. Avocetta 17:65–71

  8. Brichetti P, Rubolini D, Galeotti P, Fasola M (2008) Recent declines in urban Italian sparrow Passer (domesticus) italiae populations in northern Italy. Ibis 150:177–181

  9. Cody ML (1985) Habitat selection in birds. Academic Press, Chicago

  10. Colombo A, Galeotti P (1993) Nest-hole selection as defence measure in breeding swifts (Apus apus). Avocetta 17:1–6

  11. Cornelius C, Cockle K, Politi N, Berkunsky I, Sandoval L, Ojeda V, Rivera L, Hunter M, Martin K (2008) Cavity-nesting birds in neotropical forests: cavities as potentially limiting resource. Ornitol Neotrop 19:253–268

  12. Cramp S (1985) Handbook of the birds of Europe, the Middle East and North Africa. The birds of the western Palearctic. Oxford University Press, New York, USA, Volume IV. Terns to woodpeckers

  13. Czajka C, Braun MP, Wink M (2011) Resource use by non-native ring-necked parakeets (Psittacula krameri) and native starlings (Sturnus vulgaris) in Central Europe. Open Ornithol J 4:17–22

  14. Di Febbraro M, Mori E (2015) Potential distribution of feral parakeets in Tuscany (Central Italy): a bioclimatic model approach. Ethol Ecol Evol 27:116–128

  15. Galeotti P (1990) Territorial behaviour and habitat selection in an urban population of the tawny owl Strix aluco L. It J Zool 57:59–66

  16. Galeotti P, Morimando F, Violani C (1991) Feeding ecology of the tawny owls (Strix aluco) in urban habitats (northern Italy). It J Zool 58:143–150

  17. Genovesi P (2005) Eradications of invasive alien species in Europe: a review. Issues in Bioinv Sci 1:127–133

  18. Genovesi P, Shine C (2004) European strategy on invasive alien species, final version. Council of Europe, Strasbourg

  19. Gory G (1987) Influence du climat mediterranèen sur la reproduction du Martinet noir (Apus apus L.). L’Oiseau et RFO 57:69–84

  20. Grandi G, Menchetti M, Mori E (2016) Use of putlog holes of the Visconti Castle by breeding ring-necked parakeets (Psittacula krameri) in Pavia (Northern Italy). In: Atti del III Congresso Nazionale Fauna Problematica, Cesena, Palazzo del Ridotto, 24–26 Novembre 2016: 90–91

  21. Hernandez-Brito D, Carrete M, Popa-Lisseanu AG, Ibañez C, Tella JL (2014) Crowding in the city: losing and winning competitors of an invasive birds. PLoS One 9:e100953

  22. Howald G, Donlan CJ, Faulkner KR, Ortega S, Gellerman H, Croll DA, Tershy BR (2010) Eradication of black rats Rattus rattus from Anacapa Island. Oryx 44:30–40

  23. Ingold DJ (1989) Nesting phenology and competition for nest sites among red-headed and red-bellied woodpeckers. Auk 106:209–217

  24. Johnston RF, Selander RK (1973) Evolution in the house sparrow. III. Variation in size and sexual dimorphism in Europe and north and South America. Am Nat 107:373–390

  25. Jones CG (1980) Parrot on the way of extinction. Oryx 15:350–354

  26. Lack DL (1956) Swifts in a tower. Chapman and Hall (eds.), New York, USA

  27. Le Gros A, Samadi S, Zuccon D, Cornette R, Braun MP, Senar JC, Clergeau P (2016) Rapid morphological changes, admixture and invasive success in populations of ring-necked parakeets (Psittacula krameri) established in Europe. Biol Invasions 18:1581–1598

  28. Le Louarn M, Couillens B, Deschamps-Cottin M, Clergeau P (2016) Interference competition between an invasive parakeet and native bird species at feeding sites. J Ethol 34:291–298

  29. Luna Á, Monteiro M, Asensio-Cenzano E, Reino L (2016) Status of the rose-ringed parakeet Psittacula krameri in Lisbon, Portugal. Biologia 71:717–720

  30. Luna Á, Franz D, Strubbe D, Shwartz A, Braun MP, Hernàndez-Brito D, Malihi Y, Kaplan A, Mori E, Menchetti M, van Turnhout CAM, Parrott D, Chmielewski FM, Edelaar P (2017) Reproductive timing as a constraint on invasion success in the ring-necked parakeet (Psittacula krameri). Biol Invasions 19:2247–2259

  31. Macdonald DW, Harrington LA (2003) The American mink: the triumph and tragedy of adaptation out of context. New Zeal J Zool 30:421–441

  32. Mack RN, Simberloff D, Lonsdale WM, Evans H, Clout M, Bazzaz FA (2000) Biotic invasions: causes, epidemiology, global consequences, and control. Ecol Appl 10:689–710

  33. Menchetti M, Mori E (2014) Worldwide impact of alien parrots (Aves Psittaciformes) on native biodiversity and environment: a review. Ethol Ecol Evol 26:172–194

  34. Menchetti M, Scalera R, Mori E (2014) First record of a possibly overlooked impact by alien parrots on a bat (Nyctalus leisleri). Hystrix 25:61–62

  35. Menchetti M, Mori E, Angelici FM (2016) Effects of the recent world invasion by ring-necked parakeets Psittacula krameri. In: Angelici FM (ed) Problematic wildlife. A cross-disciplinary approach. Springer, New York, pp 253–266

  36. Mori E, Ancillotto L, Groombridge J, Howard T, Smith VS, Menchetti M (2015) Macroparasites of introduced parakeets in Italy: a possible role for parasite-mediated competition. Parasit Res 114:3277–3281

  37. Mori E, Ancillotto L, Menchetti M, Strubbe D (2017) ‘The early bird catches the nest’: possible competition between scops owls and ring-necked parakeets. Anim Conserv 20:463–470

  38. Newton I (1994) The role of nest sites in limiting the numbers of hole-nesting birds: a review. Biol Conserv 70:265–276

  39. Nice MM (1957) Nesting success in altricial birds. Auk 74:305–321

  40. Nilsson SG (1994) The evolution of nest-site selection among hole-nesting birds: the importance of nest predation and competition. Ornis Scand 15:167–175

  41. Orchan Y, Chiron F, Shwartz A, Kark S (2012) The complex interaction network among multiple invasive bird species in a cavity-nesting community. Biol Invasions 15:429–445

  42. Parau LG, Strubbe D, Mori E, Menchetti M, Ancillotto L, van Kleunen A, White RL, Hernàndez-Brito D, Le Louarn M, Clergeau P, Albayrak T, Franz D, Braun MP, Schroeder J, Wink M (2016) Rose-ringed parakeet Psittacula krameri populations and numbers in Europe: a complete overview. Open Ornithol J 9:1–13

  43. Perry D, Perry G (2008) Improving interactions between animal rights group and conservation biologists. Cons Biol 22:27–35

  44. Roche S, Bedford-Shaw A (2008) Escapee cage birds in suburbs of Johannesburg. Bird Numbers 14:2–3

  45. Sacchi R, Gentilli A, Razzetti E, Barbieri F (2002) Effects of building features on density and flock distribution of feral pigeons Columba livia var. domestica in an urban environment. Can J Zool 80:48–54

  46. Salvati L (2002) Nest site and breeding habitat characteristics in urban jackdaws Corvus monedula in Rome (Italy). Acta Ornithol 37:15–19

  47. Shwartz A, Shirley S, Kark S (2008) How do habitat variability and management regime shape the spatial heterogeneity of birds within a large Mediterranean urban park? Landsc Urban Plan 84:219–229

  48. Sicurella B, Caffi M, Caprioli M, Rubolini D, Saino N, Ambrosini R (2015) Weather conditions, brood size and hatching order affect common swift Apus apus nestlings’ survival and growth. Bird Study 62:64–77

  49. Stauffer DF, Best LB (1982) Nest-site selection by cavity-nesting birds in riparian habitats in Iowa. Wilson Bull 94:329–337

  50. Stiles EW (1980) Bird community structure in alder forests in Washington. Condor 82:20–30

  51. Strubbe D, Matthysen E (2009) Predicting the potential distribution of invasive ring-necked parakeets Psittacula krameri in northern Belgium using an ecological niche modelling approach. Biol Invasions 11:497–513

  52. Strubbe D, Matthysen E (2011) A radiotelemetry study of habitat use by the exotic ring-necked parakeet Psittacula krameri in Belgium. Ibis 153:180–184

  53. Strubbe D, Matthysen E, Graham CH (2009) Assessing the potential impact of invasive ring-necked parakeets Psittacula krameri on native nuthatches Sitta europaea in Belgium. J Appl Ecol 47:549–557

  54. Strubbe D, Jackson H, Groombridge J, Matthysen E (2015) Invasion success of a global avian invader is explained by within-taxon niche structure and association with humans in the native range. Divers Distrib 21:675–685

  55. Symes CT (2014) Founder populations and the current status of exotic parrots in South Africa. Ostrich 85:235–244

  56. Vall-Llosera M, Woolnough AP, Anderson D, Cassey P (2016) Improved surveillance for early detection of a potential invasive species: the alien ring-necked parakeet Psittacula krameri in Australia. Biological Invasion 19:1273–1284

  57. Wesolowski T (2007) Lessons from long-term hole-nester studies in a primeval temperate forest. J Ornithol 148:395–405

  58. White MJ (1986) Segregation and diversity measures in population distribution. Pop Index 52:198–221

  59. Yosef R, Zduniak P, Żmihorski M (2016) Invasive ring-necked parakeet negatively affects indigenous Eurasian hoopoe. Ann Zool Fennici 53:281–287

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The authors want to thank D. Strubbe and E. Sbrega for the useful recommendations, A. Brambilla for the help during the field-work and V. Sfondrini for the English revision. The realisation of this manuscript was supported by European Cooperation in Science and Technology COST Action ES1304 (ParrotNet). The contents of this paper are the authors’ responsibility and neither COST nor any person acting on its behalf is responsible for the use that might be made of the information contained in it. Two anonymous reviewers and the Editor kindly took the time to improve the first version of our draft.

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Correspondence to Emiliano Mori.

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Grandi, G., Menchetti, M. & Mori, E. Vertical segregation by breeding ring-necked parakeets Psittacula krameri in northern Italy. Urban Ecosyst 21, 1011–1017 (2018). https://doi.org/10.1007/s11252-018-0779-1

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  • Invasive alien species
  • Dissimilarity index
  • Bird communities
  • Nest site orientation
  • Nest heights
  • Putlog holes