Flowers for Bats campaign

Greetings! This year's Flowers for Bats campaign has come to a close. We hope you enjoyed making observations on cacti and agave this year! Read on to find out what we learned from your observations this year. Your data are making important contributions to help the USFWS understand when and where nectar sources are available for the lesser long-nosed bat, and how these nectar sources respond to changes in the environment. We hope that you will join us again next year. Your observations made at the same sites over multiple years are especially valuable in helping us to understand the variation in flowering in cacti and agave.

Agave palmeri at Molino Basin, Santa Catalinas, Photo: Camille McCollum

What you reported on saguaro and agave this year

This year, 114 observers reported data at 72 sites - thank you! The map below show sites reporting on the seven Flowers for Bats species. Darker colors represent more records reported at that site. Green outlines denote sites observing more than one species.

Our number of partners grew from eight last year to 15 this year. We also had 21 backyard observers report data for cacti and agave this year. We appreciate our partners because they provide training for volunteers, bring in data from hard to reach locations, and participate in a variety of other conservation efforts related to the lesser long-nosed bat. Our backyard observers also provide critical information about flowering timing across the urban to rural gradient.

In 2019, you captured a total of 111 onsets of open flowers for all species - 58 for saguaro, 12 for Agave americana, 35 for Agave palmeri , 6 for Agave parryi . In 2019, the average onset date for open flowers was April 13th for saguaro, May 12th for Agave americana , June 3rd for Agave palmeri , and June 6th for Agave parryi. The average duration of open flowers was 16 days for saguaros, 8 days for Agave americana , 31 days for Agave palmeri , and 13 days for Agave parryi . The two most commonly observed species, saguaro and Agave palmeri , had open flower reports at different times of the year. Saguaro flowers opened in early April, peaked in May, and ended in mid-July. There was a smaller period of flowering from August to October. Agave palmeri flowers opened at the end of May, peaked in July, and ended in September. There was a short period of late flowering in October reported at Sands Ranch near Sonoita.

Because we have partners distributed across Southeastern Arizona, we can look at how flowering time differs by location. For saguaro, the period of open flowers ranged between April and October. Urban Tucson Botanical Gardens reported flowering from April to early June, while Buenos Aires National Wildlife Refuge near the border with Mexico reported a short flowering period from mid-May to June. The McDowell Sonoran Conservancy, outside of the lesser long-nosed bat's range in Scottsdale, reported a long flowering period from April to September.

For Agave palmeri , the period of open flowers ranged from June to October. Linda Vista Trail was the earliest site to have open flowers, and Buenos Aires National Wildlife Refuge was the latest. Observers at some locations reported longer periods of open flowers, such as Linda Vista Trail, Kartchner Caverns State Park, and Sands Ranch, while Leslie Canyon National Wildlife Refuge, Saguaro National Park, and Coronado National Monument reported shorter periods.

For Agave parryi, we had fewer locations reporting, and the period of open flowers ranged from June to August. Observers at Wildlife Corridor near Patagonia and Brushy Canyon near Canelo were the earliest to report open flowers, but Canelo pass was not too far behind.

As we continue to add to this dataset, we'll begin to discover patterns of when agave and saguaro have flowers, when the peak occurs, and how climate variables such as temperature and precipitation influence flowering phenology.  We hope that you will join us again next year to continue reporting on your saguaros and agaves. You are helping us to learn more about when and where flowers are available for bats and other pollinators!

Did you earn your Flowers for Bats badge this year? See it on your Observation Deck . Thank you for your contributions to this important project!

Contact Erin Posthumus erin@usanpn.org 520-621-1670 bio

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