Dialect Discrimination by Male Orange‐Tufted Sunbirds (Nectarinia osea): Reactions to Own vs. Neighbor Dialects

Abstract

Male orange‐tufted sunbirds (Nectarinia osea) exhibit distinct song dialects throughout Israel. Recently, two distinct local dialects with a sharp boundary were discovered in a small (1.5 km2) urban neighborhood densely inhabited by 63 territorial sunbird pairs. We conducted playback experiments to determine song dialect discrimination capability by sunbird males in this neighborhood. Males of both dialects responded significantly more strongly to playback of their own dialect than to that of the adjacent dialect. In spite of the extreme proximity between the two dialect areas, we found no effect of distance to the neighboring dialect on the intensity of any the behavioral responses. We suggest that due to the complex acoustic properties of this urban neighborhood, sunbirds are extremely limited in the number of neighboring males they can assess to establish what the local song is. A stronger response to one's own dialect is therefore expected, and we discuss how local dialects could be maintained via this mechanism regardless of the very small distances between territories and dialect populations.

Subspecies status and methods explain strength of response to local versus foreign song by oscine birds in meta-analysis

“…anything not classified above 10 (Baker 1994) Melospiza georgiana (Balaban 1988) (Liu et al 2008) Melospiza melodia (Harris and Lemon 1974) [unusable] (Searcy et al 2003) (Searcy et al 2002) (Searcy et al 1997) Nectarinia osea (Leader et al 2005) (Leader et al 2002 (Nicholls 2008) [unusable] Regulus ignicapillus (Becker 1977) (Päckert et al 2001) [unusable] Regulus regulus (Becker 1977) Saxicola torquata (Mortega et al 2014) Setophaga caerulescens (Colbeck et al 2010) Sitta europaea (Matthysen 1997) Troglodytes troglodytes (Kreutzer 1974) Turdus iliacus (Bjerke 1984) Turdus merula (Ripmeester et al 2010) Vermivora cyanoptera (Kroodsma et al 1984) Vireo solitarius (Morton et al 2006) Zonotrichia albicollis (Lemon and Harris 1974) [unusable] Zonotrichia capensis (Danner et al 2011) Zonotrichia leucophrys (Baker 1982) [unusable] (Baker et al 1981) (Baker et al 1984) (Derryberry 2011) (Lampe and Baker 1994) (Milligan and Verner 1971) [unusable] (Nelson and Soha 2004) (Nelson 1998) (Petrinovich 1981) (Thompson and Baker 1993) (Tomback et al 1983) Table S1…”

Geographic variation in marmots’ alarm calls causes different responses

“…Many studies suggest that individuals discriminate among songs from conspecific populations, preferring the signal of their local population in a context of mate choice and intra-sexual competition (Baker 1982;Searcy et al 2002;Gray 2005;Boul et al 2007;Podos 2007;Nichols 2008;Uy et al 2009;Bradely et al 2013;Mortega et al 2014;Lin et al 2016); even in close populations (Leader et al 2002; but see Colbeck et al 2010;Danner et al 2011). Dialects can then act as pre-zygotic barriers and play an important role in speciation (Baker and Cunningham 1985;Slabbekoorn and Smith 2002;Price 2008;Wilkins et al 2013).…”

Variation in the ecstatic display call of the Gentoo Penguin (Pygoscelis papua) across regional geographic scales

“…In a noisy environment, vocal distinctiveness allows mates to recognize each other within a breeding season as well as across seasons (e.g., Aubin and Jouventin 1998, Leader et al 2002, Tibbetts and Dale 2007 and allows individuals to communicate information such as fitness (de Kort et al 2009) and relatedness (McDonald and Wright 2011). Variation in vocal traits may be associated with geographic isolation (e.g., Wright 1996, Dalisio et al 2015, Shizuka et al 2016, speciation (Mulard et al 2009, Pieplow and Francis 2011, Greig and Webster 2013, and range shifting (Xing et al 2013), and can even occur over short time scales in response to anthropogenic noise (Rheindt 2003, Villain et al 2016.…”