This time of the year a person can spot many different species of butterflies flying around on the Gunflint Trail. You can also spot them on the ground where there are mud puddles but according to this website it is primarily the males who puddle. The butterflies like the salt and minerals found in the puddles and the nutrients are incorporated into their sperm.
I recently noticed butterflies puddling on a dead animal and I guess they like blood, tears and urine! Andre Coatzer(a butterfly expert) suggests trying this experiment, I’ll leave that up to you to decide if you want to do it. I’ll just settle for seeing them wherever they are in nature.
A slightly strange experiment can be performed to test the ‘salt theory’ (it’s best performed when no one else is around). Firstly, find a sandy bank or a muddy patch situated in direct sunlight where there are plenty of butterflies. Next, pour a salt mixture over a wet, but butterfly-free, patch (in the less civilised version of this experiment you can replace salt with urine – butterflies are attracted to the sodium and ammonium ions). You can return to the spot later, when it is still warm outside, but before the moisture in the area has evaporated, and, if all goes well, you can photograph or observe the butterflies on your newly created “mud-puddling” spot.
Although this experiment can be very effective, it’s sometimes necessary to place a dummy butterfly on the patch as well to coax others in the area to join in. This dummy can be anything from a roadkill butterfly found stuck to the grill of your car, to a fake paper specimen. Keep in mind that all butterflies do not go to mud, so your best bet is something that is either white, resembling a butterfly from the family Pieridae, or black like the underside of a swallowtail butterfly from the Papilionidae family.