No they cannot. In fact MasterShield dealers offer the first bird and bee’s nest guarantee in the industry. Since a gutter protected by MasterShield is completely enclosed, there is no way for birds or bees to get into the gutter or underneath the system to nest. Other gutter covers can be dry, safe and attractive places for birds and bees to nest. However, since most of MasterShield’s surface lets water through, it doesn’t create an attractive nesting environment.