Song Variety in the Brown Thrasher (Toxostoma rufum)

Abstract

Field recordings and playback experiments were conducted on brown thrashers (Toxostoma rufum) in central Massachusetts in order to gather information about the consequences and circumstances of song versatility in this species. The results show the birds to have a large song repertoire in excess of 1,100 song‐types or 2,400 figure‐types. The pattern of introduction of novel figure‐types differed significantly from that predicted from a fixed repertoire model. Some song parameters varied systematically between the two individuals studied and between the different samples of one individual. Brown thrashers in the field responded differently to songs of different versatility but not to songs of different patterns of song parameter variation. Zusammenfassung Am Gesang des zu den Spottdrosseln gehörenden Rotsichelspötters Toxostoma rufum wurde die kommunikative Bedeutung der Variabiliät untersucht. Von zwei Männchen äußerte eins 1147 Gesangstypen in 1910, das andere 1116 Typen in 1971 Gesängen. Auf vorgespielte Gesänge reagierten sie stärker, wenn nur 25 statt 200 Gesangstypen darin enthalten waren. Eine Analyse von Freilandaufnahmen ergab, daß die Variabiliät und andere Merkmale des Gesanges sowohl zwischen Individuen wie auch zwischen verschiedenen Wochen derselben Saison wechseln; aber nur wenige der Merkmalsunterschiede ließen sich ökologisch wichtigen Faktoren zuordnen.

The response of the anterior striatum during adult human vocal learning

“…Many songbirds, including the most commonly studied song learning bird, the zebra finch, learn to sing their single song as a juvenile, and this song remains constant throughout life (Eda-Fujiwara et al 2012). Although this is clearly more limited than the unbounded nature of human speech, other species, such as Northern mockingbirds, continue to learn, even in adulthood, and the song repertoire of the brown thrasher can extend into the thousands (Boughey and Thompson 1981;Kroodsma and Parker 1977). Therefore, research on the genetic, molecular, and neural mechanisms underlying song acquisition in birds may inform human speech acquisition (Bolhuis et al 2010;Brainard and Doupe 2002;Doupe and Kuhl 1999;Doupe et al 2005;Enard 2011;Jarvis 2007).…”

Spectrogram cross-correlation can be used to measure the complexity of bird vocalizations

“…To test measures of song complexity using NVI with real-world examples of song diversity, we used natural bird songs of twelve species occurring in different parts of the world. Based on existing literature, expert advice, and availability of acoustic data, we shortlisted six bird species that are believed to have complex songs which included the Brown Thrasher Toxostoma rufum (Boughey & Thompson, 1981), Common Nightingale Luscinia megarhynchos ('The top 10 British birdsongs ', n.d.;Weiss, Hultsch, Adam, Scharff, & Kipper, 2014), Northern Mockingbird Mimus polyglottos (Derrickson & Breitwisch, 1992;Kroodsma, 2015), Song Thrush Turdus philomelos ('The top 10 British birdsongs ', n.d.), White-bellied Sholakili Sholicola albiventris (Purushotham & Robin, 2016), and the White-crowned Sparrow Zonotrichia leucophrys ('The Development of Birdsong', n.d.; Nelson & Poesel, 2007). In addition, we chose six more species that are considered to have comparatively simpler songs which included -the Grey-headed Canary-Flycatcher Culicicapa ceylonensis, Indian Cuckoo Cuculus micropterus, Northern Cardinal Cardinalis cardinalis, Oriental-Magpie Robin Copsychus saularis, Red-eyed Vireo Vireo olivaceus, and White-cheeked Barbet Megalaima viridis.…”

Unity and diversity in human language

“…The closest non-human analogue to this culturally transmitted diversity comes from the song systems of some songbirds (e.g. mimic thrushes like the brown thrasher [61,62]) or humpback whales [63 -65], but I know of no animal communication system that comes close to matching the range of diversity in the more than 6000 existing human languages (ethnologue currently reports 6909: www. ethnologue.com).…”