Thursday, October 13, 2011

Butterfly Migration

Birds aren't the only animals that migrate back and forth across North American twice a year. There are also approximately 75 species of insects that wander through our country's airspace seasonally. Probably the best known and most spectacular is the Monarch butterfly. Over the past two weeks I've been noticing a good number of these orange and black butterflies flying overhead. It wasn't until a stroll along the boardwalk at Coney Island over the weekend that I realized how abundant they were this year.

The amazing thing about the Monarch migration is that it is accomplished over several generations. The website "monarch-butterfly.com" explains the process:

- In February and March, the final generation of hibernating monarch butterflies comes out of hibernation to find a mate. They then migrate north and east in order to find a place to lay their eggs. This starts stage one and generation one of the new year for the monarch butterfly.

- In March and April the eggs are laid on milkweed plants. They hatch into baby caterpillars, also called the larvae. It takes about four days for the eggs to hatch. Then the baby caterpillar doesn’t do much more than eat the milkweed in order to grow. After about two weeks, the caterpillar will be fully-grown and find a place to attach itself so that it can start the process of metamorphosis. It will attach itself to a stem or a leaf using silk and transform into a chrysalis. Although, from the outside, the 10 days of the chrysalis phase seems to be a time when nothing is happening, it is really a time of rapid change. Within the chrysalis the old body parts of the caterpillar are undergoing a remarkable transformation, called metamorphosis, to become the beautiful parts that make up the butterfly that will emerge. The monarch butterfly will emerge from the pupa and fly away, feeding on flowers and just enjoying the short life it has left, which is only about two to six weeks. This first generation monarch butterfly will then die after laying eggs for generation number two.

- The second generation of monarch butterflies is born in May and June, and then the third generation will be born in July and August. These monarch butterflies will go through exactly the same four stage life cycle as the first generation did, dying two to six weeks after it becomes a beautiful monarch butterfly.

- The fourth generation of monarch butterflies is a little bit different than the first three generations. The fourth generation is born in September and October and goes through exactly the same process as the first, second and third generations except for one part. The fourth generation of monarch butterflies does not die after two to six weeks. Instead, this generation of monarch butterflies migrates to warmer climates like Mexico and California and will live for six to eight months until it is time to start the whole process over again.

So the Monarchs that we are now seeing fluttering their way through NYC are the 4th generation and they are heading to Mexico.

Anyway, while walking along the boardwalk in Coney Island Robin pointed out some butterflies at a flower garden at the end of Stillwell Avenue. What first appeared to be just a few feeding Monarchs, on closer inspections, turned out to be several dozen. These very fresh butterflies were feeding primarily on Tall Verbena. I spotted a few Cabbage Whites, Clouded Sulphurs and a pair of Common Buckeyes, but the vast majority of feeding butterflies were Monarchs.

As they fed on nectar I was able to get very close looks. None looked very worn and, in fact, their wings were perfect and fresh. One individual still had curved ends to his wings indicating that he had recently emerged. Could they have all been hatched nearby? There were so many butterflies in this tiny garden that people were stopping to take photos or videos with their smartphones.

After a few minutes of ogling the Monarchs we continued walking West along the boardwalk.

Most of the vacant lots that edge the boardwalk have either been recently developed or are in the process of being developed. The one exception is a weedy field adjacent to the Brooklyn Cyclones ballpark between West 15th and West 16th Streets. We were walking down a narrow walkway between the stadium and the field when I noticed some more Monarchs. Throughout the open field there were fairly extensive patches of flowering clover and large numbers of Monarch were nearly blanketing them. I'd never witnessed such a huge concentration of Monarch butterflies in New York City. I considered counting them, but the constantly moving butterflies made it too much of a challenge. A cold beer calling my name at Peggy O'Neills may have also played a role in my decision to just watch for a couple of minutes, then continue on my way.

If you are heading to Coney Island this coming weekend, you might want to check this spot for Monarchs.

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