Blue-headed Pionus photo courtesy of William Dymek
,
The following information concerning Blue-headed parrots in Ecuador has been provided by Ana Christina Sosa who retains copyright control.
Characteristics
There are two subspecies of Pionus menstruus in Ecuador; Pionus
menstruus menstruus (Linné) and Pionus mentruus rubrigularis (Cabanis).
The morphological differences between these two subspeices are difficult to
determine in field conditions. Size and color patterns are similar.
Forshaw (1977) points out that rubrigularis has a duller blue coloriztion
and a darker green than P. m.menstruus. Sick (1984) states that the
males in P. menstruus have a darker blue color than the females. These
traits make any comparison between subspecies difficult. In the field,
the flocking, feeding, roosting, and flight behaviors are also quite similar for
both subspecies.
An element that may distinguish these two subspecies is the call, in
that P. m. menstruus may emit a more metallic sound than P. m.
rubrigularis.
Distribution, Geography and Climate
The distribution of these two subspecies in Ecuador is well
defined. Both subspeices have a wide distributional range and are very
common. They are seperated by the Andes mountains that crosses the
country from north to south. P.m. menstruus is an eastern subspecies
whereasP. m. rubrigularisis a western subspecies. In Ecuador, both
subspecies inhabit tropical and subtropical zones (Sosa, unpublished results).
In the east, the tropical zone ranges from 0 to 600 m, and the
subtropical zone is from 600 to 2000 m. In the west, the tropical zone is
from 0 to 300 m and the subtropical zone ranges from 300 t0 1800 m in
altitude. The average temperature ranges for these zones are 23-26° C in
the tropical zone, and 19 -22° C in the subtropical zone (Cañadas 1983).
P. m. menstruus inhabits tropical and subtropical moist forest.
The annual average rainfall in moist forests is 2000-4000 mm in the
tropical zone and 1000-2000 mm in the subtropical zone (Cañadas 1983).
P. m. rubrigularisinhabits a wider range of types of forest. In
the tropical zone, it inhabits dry thorn woodland and wet forest. In the
subtropical zone, this subspecies inhabits both dry and wet forests. The
annual average rainfall in the tropical zone varies from 250 to 8000 mm and
from 500 to 4000 mm in the subtropical zone (Cañadas).
Ecological Aspects of the subspecies Pionus m. menstruus
In long-term research conducted in the Cuyabeno Reserve, in the
northeastern Amazon region of Ecuador, this subspecies shows distinctive
patterns in their habitat use and seasonal movements.
Flock Conformation
During the breeding season, P. m. menstruus forms large flocks of
about 400 individuals. During the non-breeding season they form large
mixed flocks with Amazona a. amazonica and Amazona ochrocephala.
Daily Activity
The daily activity has a defined pattern. Between 6:00 and 9:00
AM individuals begin to fly, forming noisy flocks on the higher canopy in
the forest. Foraging and feeding activities usually take place between
8:00 and 11:00 AM, and again between 2:00 and 4:00 PM. Roosting occurs
usually from 11:00 AM to 2:00 PM during the day, and again at night. In
the late afternoon between 4:00 and 6:00 PM, flocks start to fly above the
canopy with long movements around the area. This pattern changes during
rainy and cloudy weather.
Diet
In the study site, a total of 54 food items have been detrermined
to be utilized by the Psittacidae group (Sosa, in preparation). P. m.
menstruus feeds on 27% of these food items. When compared with the
feeding patterns of the 14 other Psittacidae species, P. m. menstruus is
found to be a generalist. However, P. m. menstruus prefers two types of
fruits: Protium sp. (Burseraceae) and Ficus sp. (Moraceae).
Habitat Stata and Use
P. m. menstruus is found in "Terra firme" or unflooded forest in
the higher canopy (21-30 m) most of the time. This habitat is utilized
for both feeding and roosting.
Breeding Season
The breeding season for P. m. menstruus occurs from December to early
April. This coincides withthe dry season in the study area (Cuyabeno
Reserve). A characteristic of Cuyabeno is the presence of the "Igapo" or
flooded forest which is inundated for about nine months of each year. The
dominant tree in Igapo is Macrolobium acaciifolium (Caesalpinaceae).
These are medium sized trees (6-16 m) with natural cavities in the trunk or
main branches which are utilizied by several bird species as nest sites.
Within the Psittacidae group, P. m. menstruus use these cavities as well
as two other Amazona species.
Nest Characteristics
The measurements of 9 nests of P. m. menstruus have been taken and
are summarized below:
Measurements for observed nesting sites
of P. m. menstruus
Measurement
Mean (m)
Range (m)
Entrance height above the ground
5.08
4.62-5.88
Cavity height
0.82
0.55-0.95
Entrance diameter
0.32
0.30-0.35
Cavity diameter
0.33
0.30-0.37
The nest temperatures vary during the day. During the hottest
part of the day (11:00 -14:00 hours) the temperature inside the nest is 1°
C cooler than the ambient air temerature whereas during early morning and
late afternoon hours this difference is reversed and ranges from 1.5 to 2°
C warmer inside the nest.
The first nests have eggs in December and the latest nests in
February. Clutch size is 2 - 3 eggs. Incubation period is
approximately 3 to 4 weeks, and fledging begins when chicks (pichones) are
between 8 and 9 weeks of age.
Seasonal Movements
P. m. menstruusshows seasonal movements based apparently on food
availabilty. During the breeding season in Cuyabeno,P. m. menstruusare
encountered regularly. In the non breeding season, from August to mid -
December,P. m. menstruusis very commonly encountered during the time
when fruit abundance is highest. However, during the rainy season (April to July), the frequency of flock observations decreases by 80%.
Conservation
P. m. menstruusis still very common in eastern Eucador. Some of
the potential threats toP. m. menstruussurvival are habitat reduction
and hunting. P. m. menstruusfeeds on crops, especially corn, and
farmers occasionally shoot and kill marauding birds. This subspecies is
not a target species for poachers nor for local pet bird owners.
Pionus menstruus rubrigularis
Ecological Considerations
P. m. rubrigularishas not been studied in as great a detail as
has P. m. menstruss, however, periodical observations have been conducted
in some areas along the western slopes of the Andes -- especially in the
Chiriboga old road, and in the slopes along the southern part of the
Colonche mountains, from eastern Valdivia to Santa Rosa.
Flock conformation
Flocks ofP. m. rubrigularisare also formed by groups of 80 to
120 individuals. The flocks observed were intraspecific flocks in all the
observations (n=32).
Daily activity
The daily activity of P. m. rubrigularis is very similar to P. m.
menstruus and exhibits a daily behavior pattern similar to that described
for P. m. menstruus.
Diet
The diet for P. m. rubrigularis is based on preliminary observations. In
coastal areas, P. m. ruburigularis is feeding primarily upon Spondias
purpurea (Anacardiaceae), but is known to be feeding in open farmlands,
especially in corn fields and orchards.
Habitat and Strata Use
P. m. rubrigularis is usually found in dense forested areas, but
it now appears to be common in open farmlands as well. They prefer the
higher canopy in both types of habitat. Parrots are usually observed
flying above farmlands.
Breeding Season
The breeding season forP. m. rubrigularistakes place from
December to early April, similar to P. m. menstruus. In the western
slopes of the Andes these months coincide with the rainy season. Nests of
P. m. rubrigularis have not been observed to date, therefore, information
about breeding and nest characteristics are sadly lacking.
Seasonal Movements
As in P. m. menstruus,P. m. rubrigularisalso shows seasonal movements.
During the breeding season, the Blue-headed parrot populations are more
abundant. During the non-breeding season populations remain in a
relatively constant number, but fewer than during the breeding season.
Conservation
Despite the fact thatP. m. rubrigularisis still very common in western
Ecuador, human activities affect their numbers through habitat reduction
and hunting. P. m. rubrigularisfeeds on crops which results in the
birds' destruction at the hands of farmers who shoot the birds with guns.
Otherwise,P. m. rubrigularisis not a target species for poachers nor for
local pet markets.
Both subspecies are mainly considered as threats to farmer's crops
and are seen as pests rather than potiential exploitable resources by the
local people.
LITERATURE CITED
Cañadas, L. 1983. El mapa bioclimático y ecológico del Ecuador.
Ministerio de Agricultura y Ganadería-PRONAREG. Quito, Ecuador.
Forshaw, J. M. & Cooper, W. T. 1977. Parrots of the World. TFH
Publications, Inc.
Sick, H. 1984. Ornithologia Brasileira, uma introduçao. Vol. 1 3rd ed.
Editora Universidade de Brasilia. Brasilia
Sosa, A. C. (in preparation) "Feeding ecology of 15 species of Psittacidae
in the Cuyabeno Reserve, northeastern Amazonia, Ecuador".
Sosa, A. C. (not published) 1993. "Distribution, habitat, status and
threats of the Psittacidae in Ecuador". Distribución, habitat, estado
poblacional y problemático de los Psittacidae en el Ecuador.
This work appears courtesy of the PBA. All rights retained by the author.
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