Seasonal honey bee colony loss rates in the United States, 2008-2021. Annual loss estimates (from one 1 April to the next 1 April) combine winter (1 October – 1 April) and summer (1 April – 1 October) losses. The loss rate was calculated as the total number of colonies lost divided by the number of colonies “at risk” during the season. Colonies at risk were composed of viable colonies and new colonies made or acquired, while excluding colonies sold or parted with. Graphic: Bee Informed Partnership