Summer heat can be hard on bees. If there is a shortage of water nearby some bees travel up to five miles to find it. They can get overtired, overheated and perish. Try to always make some safe fresh water available in your garden so they need not undertake those deadly journeys. Here is a sweet blog post on this theme.
There are many possibilities that scientists ponder when it comes to finding a whole lot of dead bees around the place.
Pesticides often kill them. So do loss of habitat, mites, and pathogens, which can even lead to the dreaded Colony Collapse Disorder where an entire hive is decimated. Less likely causes are genetics, malnutrition, immune system deficiencies. Then there is pure old age and unfortunate events.
San Diego County, California is home to 600 bee species, and the honeybee is the most common. In La Jolla, dead bees are being found by the dozens in and around town. One woman saw about two dozen dead bees on sidewalks during her evening walks in July.
Hilary Kearney is a beekeeper who manages hives in San Diego County, including the bees at San Diego Natural History Museum and San Diego Zoo. She has noticed more pesticide poisonings of bees in La Jolla, Point Loma, and Del Mar.
Much of this can be due to resident gardeners or hired landscapers using pesticides. If pesticide is applied improperly, or used to treat flowering plants, an entire bee colony can be lost in one afternoon. The bees consume poisoned nectar and bring it back to the hive to share with their nest mates. This ends in the sad tragedy that they all die.
This unrelated 6:19-minute video by Kurzgesagt - In A Nutshell discusses some causes of bee deaths:
It is ‘normal’ to see some dead bees when outdoors. The oldest bees are the foragers, and sometimes they just die of exhaustion or old age while they are out collecting nectar and pollen.
So, how many dead bees are too many, and should sound an alarm?
According to Bodil Cass, an agricultural scientist with San Diego County who directs the county’s honeybee protection program, there is no need to be concerned about seeing a dozen dead bees.
General research reveals that an average of 1,000 (800 to 1,200) bees from all hives die daily while out foraging. Their average lifespan (except for winter bees) is 4-6 weeks. Either they are old and exhausted, or they run into trouble. They fall to earth all over the place, so you won't usually see a big pile of dead bees. Consider that there are 20,000 to 60,000 honeybees in a beehive, and the queen bee lays 1000 to 2000 eggs every day. This is how hive population regulates itself.
We have blogged about many incidents where tens of thousands to millions of dead bees are discovered clustered in rural areas. These staggering numbers almost always are due to pesticide poisoning.
Coming back to the pesticides theme, though, it is highly encouraged that people look for more natural ways to deal with pests than by using pesticides. Fertilizer can be added, plants can be pruned or moved to adjust exposure to sunlight, and there is an array of natural products.
If you decide to use pesticides anyway, do so late at night so they dry, and the toxic nature is less potent when pollinators show up early. One of the best things you can do if using pesticide is read the product labels. They must reveal on the label what to do to protect bees if they are toxic to them. And remember, if in doubt, throw it out!
Want to save the bees? Help the bees? Plant bee-friendly flowers wherever you can. Even better is to plant flowering trees if you have the space. These endure over long periods of time and are always there to provide vital nutrition to native bees and honeybees.