The very buoyant Comb Ducks often swim with curved necks,
humped backs and tails held well clear of the water.
While swaggering waddles cause them to be somewhat ungainly ashore,
drakes are noted for high steps and long strides.
[PREV] At the onset of the life-giving rains,
Comb Ducks detach themselves from flocks and disperse.
While monogamous in marginal habitat, polygamy is apparently
the norm in optimal terrain.
Dominant drakes (harem-masters) control at least two,
and sometimes as many as four females.
The generally weak "pair" bonds persist only until egg laying commences.
Up to ten females may accompany harem-masters, although all are probably
not members of the family group. When more than one mate
is attended simultaneously, this is known as harem polygamy,
but drakes also engage in successive polygamy when two or
more females (even up to five) are serviced in succession.
Breeding groups are formed on the nesting grounds,
and while harem-masters protect their females, territories or nest
sites are not defended.
Unmated females may temporarily join harems and are tolerated by
the mated or "queen" females, but are relegated to low positions in
the dominance order. Harem-masters accept, court, or are overtly
aggressive to new females seeking to join established harems.
Unattached males cluster around areas occupied by harems,
keeping watch from elevated perches from which they descend to rape mated
females, or court unmated hens whenever possible.
Harem-masters aggressively challenge intruders‐that normally concede
defeat--though repulsed males tend to linger nearby awaiting another
opportunity.
If challengers stand their ground, fights may persist for a minute or longer,
terminating only when one combatant ultimately retreats or
loses his balance and topples over.
Nesting in tree cavities 20-30 feet above the ground or within holes
in the walls of isolated buildings,
Comb Ducks also seek tree forks and the nests of other birds,
including vultures, Jabiru and Hamerkop
storks, fish-eagles and hawks. The African ducks
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benefit to some extent from tree-damaging elephants, because dead trees are
subsequently hollowed out by wood-boring insects, providing ideal nest cavities.
Nesting neotropical females may select dead Burti palms or large branches
festooned with epiphytic plants, sometimes as far as three miles from water.
They also nest on the ground if cavities are scarce, generally in tall grass
or among stones.
Females prospect for cavities throughout the day,
but are most active in the early morning, when they
clamber along branches, peering into all holes,
sometimes competing with conspecifics for prime
cavities. Nests are apparently not lined with down.
Ascertaining typical clutch sizes is difficult due to multiple females
in communal breeding groups, but nests exceeding ten eggs probably
represent the efforts of more than one female.
Dump-nests may accommodate more than 50 eggs.
Typical clutches consist of 6-11 eggs that are incubated for about a
month, probably by the dominant female alone. Within a day or so of hatching,
ducklings leap from elevated nests when summoned by their mothers,
usually in the early morning, but females delay calling if predators are lurking nearby.
While not involved in brood care, harem-masters maintain vigilance over territory areas.
African broods may consolidate in loose crechès on larger pans, where
duckling predation can be high. Subsequent to fledging at about ten weeks of age,
juveniles remain with females until the molt exodus.
Despite their spotty distribution, Comb Ducks can be locally numerous.
While possibly no more that 6,000 inhabit southeast Asia,
between 100,000 and a million ducks reside in Africa.
The neotropical birds have declined rapidly in Argentina due to
the dosing of rice with the pesticide Parathion,
deforestation and uncontrolled hunting, especially by
large groups of tourist-hunters. Nevertheless,
possibly as many as 40,000 dwell in Venezuela,
and no less than 20,000 are believed to reside in
Brazil, with over 5,000 recorded at a single site alone in 1992.
The overall South American population could be as great as 100,000 ducks.
Due to their polygamous tendencies, captives are ideally maintained as trios
because drakes can become aggressive toward single females, and all too
often abuse them.
The African birds are firmly established in North American collections,
but the neotropical ducks are scarce.
Conversely, the South American ducks presently outnumber their Old
World counterparts in Europe.
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