Following torrential rains during spring, Tulare Lake was refilled for the first time in 30 years attracting migratory waterfowl but creating a problem of botulism. At present migratory birds are moving southward along the Pacific Flyway and are congregating on the lake.

The lake is receding with the refilling of aquifers, surface evaporation and abstraction.  This has created a problem of rotting vegetation around the boundary of the lake predisposing waterfowl to ingesting botulinum toxin. 

It is apparent that in 2023, Tulare Lake will be responsible for extensive losses following the situation in 1983 when the lake was previously refilled. 

If mildly affected birds showing paresis are gathered and are provided with support therapy, they will survive.  Unfortunately, high mortality among the population establishes a cycle of toxicity as maggots feeding on carcasses serve as an intermediate in the chain of transfer of botulinum toxin to unaffected birds.  At present wildlife biologists are gathering dead and dying birds with more than 3,000 removed from the lake during September to avoid a mass die off.