Every year, since 1906, April 1 is celebrated as the World Bird Day, which is held within the UNESCO program “A Human and a Biosphere”. Exactly on that day the International convention on birds protection was signed and since then April 1 is not only a day of signing of Convention but also the World Bird Day.
Details: http://www.menr.gov.ua/press-center/news/150-news28/6050-1-kvitnia-v-ukraini-vidznachaiut-mizhnarodnyi-den-ptakhiv
