Why are heavily vegetated floodplains generally unsuitable for successful Belted Kingfisher reproduction?

They lack the required exposed, unvegetated earthen banks for tunnel excavation

Although heavily vegetated floodplains might offer excellent foraging opportunities due to the abundance of water and potential food sources like small fish, they are explicitly mentioned as unsuitable for successful breeding activities. The critical limiting factor here is the nesting requirement. Belted Kingfishers must excavate long tunnels in stable, vertical earthen banks that are generally unvegetated or naturally cut away. Areas characterized by dense vegetation coverage across floodplains often lack these exposed soil faces, preventing the birds from establishing the necessary excavation sites required to raise their young, even if they stop there to hunt.