You most likely have heard that Arizona is a special place for Hummingbirds. Both the numbers and diversity of hummingbirds peak in Southeastern Arizona in August and this is just one more reason that Arizona is awesome in August! On this surface this seems rather odd. Why would hummingbirds be most abundant when it is so hot that many of us don’t want to leave our air-conditioned homes? The answer is multi-faceted!
One of the main reasons for this spike is the monsoon storms that occur this time of year. All of the moisture that these impressive storm systems drop on the region results in a “second spring” where much of the vegetation greens up and flowers. It is these flowers that now carpet the moist canyons, desert uplands and mountain sides that bring hummingbirds from different areas to southern Arizona. The local nesters that were here in spring remain and are joined by hummingbirds that already nested further north, but are already headed south on migration. They time their journey south so that they too can enjoy the productive “second spring.” A third group of hummingbirds also arrives in August that has been following the flower producing rains northward from Mexico. Often this is when rarities from south of the border appear in Arizona.
This helps explain the why August is the best month for Hummingbird viewing, but why is southern Arizona such a haven for Hummingbirds in the first place? The answer lies in geography. Southeastern Arizona is a hotspot of biodiversity for many types of plants and animals because so many habitats and life zones overlap in this area. The varied array of habitat types is part of the explanation. Within a day’s drive of Tucson we have desert, grasslands, mesquite bosques, riparian areas, oak juniper, Douglas fir and ponderosa pine forest all the way to tundra on some of the higher sky island peaks.