All larks species occur in the Old World and Australia. Only one species, the Horned Lark (Eremophila alpestris), is native to North America. Their habitats vary widely, but several species live in dry regions.Interspecific hybridization occurs in at least three genera, Mirafra, Galerida, and Alauda.
There could also be hybridization in the genus Certhilauda. When re-examining the Karoo Lark (C. albescens) complex in Africa, Ryan et al. (1998) described a new species, the Barlow’s Lark (C. barlowi, also known as Calendulauda barlowi). Intermediate phenotypes between this species and the Karoo Lark may be the outcome of hybridization, but further research is recommended.
Bergmann’s Rule predicts a larger body size in colder areas within warm-blooded vertebrates. This rule was tested in Galerida larks taking into account hybridization between Crested Lark (G. cristata cristata) and Magreb Lark (G. c. randonii) in Morocco (Guillaumet et al., 2008). A previous study already showed that natural selection (and not hybridization) accounts for the phenotypic variation in these larks (Guillaumet, Crochet & Godelle, 2005).
Guillaumet, A., Crochet, P. A. & Godelle, B. (2005). Phenotypic variation in Galerida larks in Morocco: the role of history and natural selection. Molecular Ecology 14, 3809-3821.
Guillaumet, A., Ferdy, J. B., Desmarais, E., Godelle, B. & Crochet, P. A. (2008). Testing Bergmann’s rule in the presence of potentially confounding factors: a case study with three species of Galerida larks in Morocco. Journal of Biogeography 35, 579-591.
Ryan, P. G., Hood, I., Bloomer, P., Komen, J. & Crowe, T. M. (1998). Barlow’s Lark: a new species in the Karoo Lark Certhilauda albescens complex of southwest Africa. Ibis 140, 605-619.