When Erwin Stresemann realised that hybridisation among birds-of-paradise might be an explanation as to why so many of the described species were so rare, he examined many controversial specimens and, during the 1920s and 1930s, published several papers on his hypothesis.
Cando Erwin Stresemann se decatou de que a hibridación entre aves do paraíso podería ser unha explicación de por que moitas das especies descritas eran tan raras, examinou moitos espécimes controvertidos e, durante as décadas de 1920 e 1930, publicou varios traballos sobre esta hipótese.