The sampling revealed Thursday by analyst Gene Munster with Piper Jaffray offers a look at early adopters of the Verizon iPhone, who were polled in New York and Minneapolis. Munster noted that his sample size was smaller than with previous launches on AT&T because lines were shorter than usual for the first day of sales.
Of those polled, 63 percent indicated they are already Verizon customers. Just 8 percent were switching from AT&T -- less than the 18 percent switching from Sprint and 13 percent from T-Mobile.
Those buying a Verizon iPhone 4 on day one are mostly new to the platform. Just 8 percent of buyers were upgrading from an older iPhone, as the handset was previously exclusive to AT&T in the U.S.
Of the rest, 28 percent were switching from Research in Motion's BlackBerry platform, 13 percent were making the jump from Google Android, and 8 percent were coming from Nokia phones. The remaining 45 percent were switching from other phones, including "feature phones" that are not as powerful or connected as modern smartphones.
A quarter of early adopters polled by Piper Jaffray already own an iPad. Of the 75 percent that do not own Apple's touchscreen tablet, 43 percent indicated they are likely to buy one in the next 12 months.
Fewer of Verzon's first-day customers opted for the high-end 32GB capacity iPhone 4 than AT&T customers when the GSM model launched in June 2010. Only 28 percent of buyers on Thursday purchased the 32GB model, compared to 54 percent on AT&T last June.
Because the small survey shows signs of limited cannibalization of AT&T iPhone customers, Munster said his initial estimates of a 22 percent reduction in iPhones on AT&T could be too aggressive. He is currently calling for sales of 2.9 million iPhones on AT&T's network in the quarter, but said that number will likely go higher if the survey proves accurate.
The survey also paints a slightly different picture than an initial poll revealed in January, and conducted just before the Verizon iPhone announcement. ChangeWave found, in a much larger sampling of 4,050 U.S. wireless customers, that 16 percent of AT&T customers said they would be likely to switch to Verizon.