Rosary pea seed pods. Close-up of open seed pods of the rosary pea plant (Abrus pectatorius). Inside each pod are red and black seeds, which are attractive to birds as food. As a seed passes through a bird's digestive tract, the tough outer seed coat is weakened, thus aiding germination of the seed when it later passes out of the bird in its faeces. However, the seeds are poisonous to humans. They cause severe gastroenteritis, which leads to dehydration and shock. A. pectatorius is a climbing plant native to tropical regions. The seeds measure around 6 millimetres in length.