Black-Birders—also known as Black Birds, were usually ruthless organized groups of armed regularly waylaid slaver thugs who made a living by monitored and abducted free black residents and fugitive runaway slaves over various black community locations, in New York City and Philadelphia, to illegally sell into slavery in the antebellum southern states along across multiple state lines such as Alabama and Mississippi. At the same time starting in the 1830s, pro-slavery doughface sympathizers—many tied to Southern economic interests—operated gangs that partook in kidnapping free Black men, women, and children to sell them into slavery in the South. These “slave catcher” gangs were commonly known in abolitionist circles as more colloquially, Kidnapping Clubs, sometimes with the support and participation of policemen and city officials.