On this day in 1997, Paul Lehman was indulging in what has become a popular autumn Cape May pastime: sorting through flocks of swallows. Under optimal conditions, big swallow flocks can be found anywhere around the southern end of Cape Island; Lehman happened to be at the South Cape May Meadows. As he looked through a flock of 50 to 75 Tree Swallows, he spotted a martin. Any November martin would be highly unusual as virtually all Purple Martins leave the state by the end of September (Walsh et al. 1999). After a few seconds, the martin headed off toward Cape May Point State Park and Lehman returned home to check some books and get the word out to the locals. Further glimpses of the bird were had by various birders over the course of the afternoon, and the identification seemed to come down to a choice between Purple and Brown-chested Martins. The only previous confirmed North American record of Brown-chested Martin was a bird that was collected on Monomoy Island off Cape Cod in Massachusetts on 12 June 1983.
Lehman (1998) tells the story in detail: how after the first day of the martin's stay, local birders were left with the feeling that it was an odd Purple Martin. More research was done and out-of-state birders were consulted overnight. The locals were out in force the next morning, despite unpromising weather, and the martin was relocated on the west side of Cape May Point by the gingerbread church. The martin's companions included late Barn and Cliff Swallows, late Chimney Swifts and "as many as 5 Cave Swallows." The martin was determined to be a Brown-chested Martin and the twitch was on.
The martin was seen until 15 November, when it seemed to be in poor condition; it was not seen afterward and was presumed to have succumbed during the night. Before then, as many as a thousand birders may have participated in what one of my birding friends fondly remembers as "Martin Madness."
Lehman, Paul. 1998. Brown-chested Martin in Cape May!: First New Jersey and Second Documented North American Record. Records of New Jersey Birds 24:66-69.