These children are students at Public School 234 in New York City. They, along with hundreds of schoolchildren around the world, are part of Project PigeonWatch, run by Cornell University. The students are helping the Cornell University ornithology project to study pigeons. They are trying to figure out why pigeons come in so many colors and how pigeons choose their mates.
Ornithology is the branch of zoology which deals with birds.
Cornell University is located in Ithaca, New York. These students are in New York City, where there are many pigeons. Pigeons mate all year round, instead of just in the spring. Answers will vary. Pigeons are used to help locate people lost at sea because they are attracted to humans.