Recently while I was taking a morning walk before the temperature began to soar; a female eastern tiger swallowtail slowly flew in front of me. In fact, the large butterfly seemed to glide more than fly. When she did beat her wings, they flapped slowly. As I watched, the butterfly landed on the leaves of a nearby shrub. She chose to land in a spot that was bathed by the light of the rising sun. Upon landing she kept her wings outstretched and remained motionless for quite some time.
This butterfly was warming up. This something each butterfly does every day of its life. Like an airplane, before it can fly efficiently, it must warm up.
The butterfly is a cold-blooded animal. This means that it cannot control its body temperate such as warm-blooded animals like you and me. Consequently a butterfly’s body temperature reflects the air temperature. In comparison, our body temperature remains constant at all times.
The next time you are out and about on a sunny, cool morning be on the lookout for basking sites. Once you find one, you can often find butterflies there day after day,
In the case of the butterfly, most are not seen flying about when the temperature dips below 55˚F. In fact the ideal temperature for butterflies to be winging about is roughly between 80 and 100˚F.
When the temperature is below this zone the insect’s flight muscles are not capable of contracting as quickly as they are when temperatures are high. In addition, butterflies expend more energy moving their flight muscles when it is colder.
Since butterflies need to start moving about as quickly as possible to escape predators and find food and mates, it behooves them to take to the air as soon as they can each day.
One way they are able to do this is to take advantage of the warming effects of solar energy. The butterfly that drifted to a nearby bush in front me was doing just that. She positioned herself to maximize the amount of solar radiation striking her wings and body. This would allow her to begin daily activities much sooner than would have been possible if she perched in the shade.
Dark butterflies, such as the female eastern tiger swallowtail, are able to fly sooner in the day than butterflies that are lighter in color. The reason for this is darker colors absorb more solar energy than light colors.
As you can see, one of the best times to watch or photograph butterflies in your backyard is early in the morning. During this special time of day if you find a basking butterfly, it will often remain motionless longer than it would if you found it in your garden later in the day. As long as you do not disturb a basking butterfly, you can take pictures of it to your heart’s content.
You can create additional butterfly basking sites by placing large, flat, dark-colored stones about your garden and yard.