Attract martins to your newly placed martin house with this Nature House Purple Martin Morning Vocalization CD on a 2 hour loop. Adult male martins at established colonies offer vocalizations each morning between 4 AM and 6 AM, attempting to attract subadult martins to the area. This is a two hour long loop of the original 71 minute long CD, recorded at a 300 pair colony in Washington, IL. Playing this is great for inviting these birds to your new housing. The CD version of this can be purchased at the following Amazon link: https://amzn.to/3r4ENr5