Geoscience Reference
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us roseus ). These birds gather and breed by the millions next to high-salinity lakes
in this area. Feeding, flirting, and fornicating flamingos significantly trample the
nearshore and shallow-water muds of these lakes, which these birds also use for
bathing. They further contribute to this “flamingoturbation” by constructing thou-
sands of nests out of gooey shoreline mud. Their nests look like miniature volca-
noes, wider at their bases (30 cm, or 12 in) than at their tops (20 cm, or 8 in), and
about 15 to 20 cm (6-8 in) tall, with a shallow bowl at the top to secure the egg
clutch.
Flamingos mine the lakeshore mud, which they do by dragging it with their
beaks or scooping up mud in their bills and spitting it onto the nest. These actions
result in shallow rings or semi-circles (“moats”) around each nest. Mixed in with
the mud shaping the nests were feathers, vegetation, and (somewhat morbidly) the
bones of dead flamingos. Insects may add their own traces to the nests, burrowing
into and forming brooding cells in their sides, and plant roots sometimes invade
abandoned nests. Based on their detailed descriptions of these modern nests, the re-
searchers were confident that they could easily identify ancient examples. Not sur-
prisingly,then,theypromptlydidthisinthesamestudyarea,discoveringflamingo-
nest trace fossils that were more than 10,000years old, and sometimes directly next
to or beneath modern nests.
Probably the most important aspect of these nests, though, is how both extant
and older nests affected lakeshore environments and river deltas emptying into the
lakes. Nests were normally spaced 1 to 2 m (3.3-6.6 ft) apart, either forming lines
or clustered. However, wherever nests were closer together, the “moats” between
themjoined,turningtheselowareasintosmallpondsorcanalsthroughwhichwater
could easily accumulate or flow, respectively. Both the trampling and nests also
compacted lakeshore sediments so that these were less porous, acting more like ce-
ment. These “case-hardened” surfaces then resisted wave or stream erosion, which
accordingly also influenced where water flowed in delta channels. Thus through a
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