In 2020, you captured a total of 122 onsets of open flowers for all species - 75 for saguaro, 42 for Agave palmeri, 3 for Agave americana, 1 for Agave parryi, and 1 for Agave deserti.
The two most commonly observed species, saguaro and Agave palmeri, provide nectar for bats at different times of the year. Now that we have multiple years of data, we can start to look at timing of nectar availability in these species.
In the past three years, saguaro flowers opened in early April, peaked in May, and ended in mid-July. In 2020, the average onset date for open flowers in saguaro was May 17th, and the average duration of open flowers was 21 days. The average date on which saguaros had at least 75% of flowers open was June 5th.
During these years observers also recorded a second smaller period of flowering ranging from August to October.