Do you ever see flocks of birds in your yard that show up in droves one year, but are completely absent the next? Some nomadic species such as Pine Siskins move based on the availability of food and habitat. It’s called irruptive migration, and it sometimes leads to backyards full of siskins. While these flocks are a delight for bird watchers, the dense groups can easily transmit diseases such as salmonellosis.

This episode is brought to you by Wild Delight Bird Food, which aims to support wild bird populations with clean, nutritious ingredients in every blend. Available at Chewy.com.

More info and transcript at BirdNote.org.

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