Anglers on vast, open water often look for a flock of feeding birds to indicate fish location and activity.Â For smaller waters, indicators might be much smaller.
In spring and summer, whirligig beetles are alone or in loose, small groups.Â They zig and zag so rapidly, that I cannot recall ever observing a fish try to eat them. With cooler weather, whirligig beetles congregate in large numbers.Â One theory is that as their metabolism rate lowers, there is added benefit of safety in numbers. These large masses of floating water beetles can provide information that may be of use to the fisherman.
A disturbance of the waterâ€™s surface from above, such as a pebble in a pond, will create waves expanding outward. A similar event can occur from underwater. Whirligig beetles have two sets of eyes: one above, and one below water.Â One nervous solo water beetle would be easy to miss. However, fish presence or movement that may not have been enough to create a surface ripple can be detected by this floating mass of insects and a ripple of alarmed energy activity bounces to each member of the group.
This seasonal gathering can provides a clue of fish activity in a quiet pool that might have been overlooked.Â Plus, kids love bugs, and water.Â So a massive collection of black button water bugs that act like a sonar can add to the enjoyment of a late season fishing trip.