According to the folk calendar - Mark Klyuchnik

On May 8 (April 25 according to the old calendar style), people celebrate Mark Klyuchnik. So the day was named in honor of St. Mark of Alexandria, an apostle of the 70 and an evangelist, whose memory is venerated by Christians on this date. Mark was from Jerusalem and was raised with the Christian faith in his heart. During his lifetime, he found Christ and was a disciple of the apostles Paul, Peter and his uncle Barnabas. The saint went to preach the faith of Christ in Cyprus, Libya and Egypt. In Alexandria, Mark organized the construction of a temple, after which he was elected to the post of Bishop of Alexandria. However, for his active preaching, he was captured by the pagans and tortured to death. The people called Mark the Keymaker, believing that he comes in the spring with the keys to open the heavens for heavy rains. The peasants in the fields read special spells for rain, prayed to the saint for moisture for the sown seeds so that they would not dry out. They just needed abundant watering from the rain, since applying water from the well to the entire field was unrealistic work. The day was also called a bird holiday, or bird fasting. It was believed that songbirds returned from warm regions on Mark's day. After the flight, they were tired, so their caring owners prepared a treat for them in the morning: hemp seeds were scattered in the yard. To ensure that the birds stayed nearby and did not fly away into the forest, men knocked together bird houses and mounted them higher. In some regions, residents went to catch siskins, believing that they would bring happiness to their owners. The housewives were busy with housekeeping that day - they cleaned the house, swept the floors with nettles, and wiped the shelves with its tincture. They said that nettle helped get rid of evil spirits. All clothes were taken out into the fresh air to air. In the fields on Mark's Day, peasants were sowing buckwheat. If you watched songbirds fly to a hemp field on Mark Klyuchnik, you were preparing for its bountiful harvest. Heavy rains also promised a high harvest. The sunny weather on this day foreshadowed a hot summer season. Seeing a high rainbow meant the onset of fine days, and a low rainbow meant bad days. The cuckoo's cuckooing signaled the end of the cold weather.