E16. What if the secret to raising more babies was to never raise a single one yourself? Dr. Chris Balakrishnan, Associate Adjunct Professor of Biology at East Carolina University and co-founder of Nerd Nite, has spent his career studying the strangest birds on the planet: the ones that outsource parenthood entirely.

In this episode you'll hear about:

• The evolutionary arms race between brood parasites and their hosts, from mimetic eggs to alien-looking chick mouth patterns
• How the "password hypothesis" explains how brown-headed cowbirds avoid imprinting on the wrong species
• Why host-switching in African parasitic finches can drive the rapid formation of new species

All audio, video, and images in this episode are either original to Okay, But... Birds (© Okay Media, LLC) or used under license/permission from the respective rights holders. Bird media from the Macaulay Library is used courtesy of the Cornell Lab of Ornithology as follows:

• Brown-headed Cowbird audio contributed by Wil Hershberger, ML94262
• Brown-headed Cowbird audio contributed by Wil Hershberger, ML516718
• Redhead audio contributed by Jessie Berry, ML139672
• Canvasback audio contributed by Arthur A. Allen, ML3537
• Greater Honeyguide audio contributed by Mike Andersen, ML140981
• Pin-tailed Whydah audio contributed by Myles E. W. North, ML14489
• Village Indigobird audio contributed by Myles E. W. North, ML14484
• Zebra Finch (Australian) audio contributed by Vicki Powys, ML226233
• Prothonotary Warbler audio contributed by Wil Hershberger, ML85158
• Kirtland's Warbler audio contributed by Rudolph Little, ML13982