Robin Turnau will succeed Mark Vogelzang as president and c.e.o. of Vermont Public Radio, the network announced yesterday. Vogelzang received a “really terrific offer” to lead a national fundraising effort for public radio stations, he said yesterday during an interview on VPR’s Vermont Edition. Vogelzang, top executive since 1993, led VPR through a major service expansion. Turnau, v.p. of development since 2004, has been with VPR for 20 years.