that can sometimes displace bell miners is the similarly aggressive noisy miner, but in general noisy miners prefer areas with little understory. Bell miners are able to suppress the numbers of competing species in territory that they hold for years. However, bell miner colonies have clearly defined territorial boundaries, and beyond those boundaries the local bird assemblage resumes its normal diversity. Feeding Bell miners specialize in consuming insects known as psyllids and their associated young nymphs, sweet lerps, and other psyllid secretions. Psyllid products may consist of up to 90% of the bell miner's diet. Bell miners forage primarily among leaves, branches, and loose bark in the canopy, generally at least 8 m in height, but they do descend to the dense understory. There is a theory that bell miners 'farm' psyllids by excluding other psyllid-eating bird species from a large enough territory, that the miners themselves do not require all the psyllids from in order to sustain the colony. One hypothesis under the farming theory is that the bell miners may selectively eat only older nymphs, or may often eat the lerps and leave the nymph unharmed. Evidence for this theory has been mixed. An early study of stomach contents did not find supporting evidence for this theory, as bell miner stomachs did not contain the higher lerp/nymph ratio that would have been expected. However, a later behavioral comparison between bell miners and noisy miners did observe that bell miners carefully used their tongue to remove lerps, which left the nymph intact. In contrast, noisy miners pried the lerp and nymph off with their beak and consumed both. When bell miners are removed, psyllid colonies are generally quickly decimated by the other forest bird species that move into the miners' former territory. Although psyllids are the primary food source, like most honeyeaters, bell miners have also been recorded drinking nectar from eucalyptus, banksia, and mistletoe flowers, as well as eating various other insects, including spiders, beetles, weevils, moths, and wasps. Bell Miner Associated Dieback Bell miners are so closely associated with eucalyptus dieback that the phenomenon has been named Bell Miner Associated Dieback (BMAD). Concern about BMAD has led to the formation of the BMAD Working Group, the 2004 BMAD Strategy, the 2005 BMAD National Forum, the 2006 BMAD Literature Review, and continues to be an area of active research. Eucalyptus dieback involved complicated ecosystems with numerous variables and