I've never found any of the Herons or Egrets to be difficult to get close to. Maybe its your location. Down here I can pretty much walk to within 20 feet or so of most any of them. Heck I had a Great Blue come to me....landed right next to me.
Location definitely has a lot to do with it.
Here in the area where I live, there are a lot of Great Blue Herons. . But they rarely ever have any encounters with humans because the human population is so sparse. . So when I see a GBH, I literally cannot approach to within a hundred and twenty five yards without the heron getting scared and flying off. . They are absolutely terrified of any human, and will not allow one to get anywhere near them.
Hence, the only way I can get close enough to photograph them is to shoot them at their rookery, where they are pretty much anchored to their nests and their young, and have no choice but to tolerate me..........albeit uncooperatively and grudgingly.