Densities

Standing Crop Nest Count: A total of 48 nests along 26.3 km of line transects served as the analyses of the standing crop count method. This represents a nest

Table 8.1 Availability and choice of habitat types for nest construction

Habitat

Table 8.1 Availability and choice of habitat types for nest construction

Habitat

Class

Habitat characteristics

availability

choice

Forest Composition Dominated by

% Transects

# of nests % of nests

1

dry heterogenous

73.0%

255

97.4%

2

homogeneous Monopetalanthus

3.3%

-

-

3

Gilbertiodendron

3.1%

1

0.4%

4

wet (temporarily) heterogenous

3.6%

-

-

5

wet (permanently) heterogenous

17.0%

5

2.2%

Availability of habitat types (class 1-5) along transects (in %) and habitat choice represented by the absolute number (#) or relative proportion (%) of nests found in each habitat type. Habitat types are classified as follows: 1. heterogeneous primary forest on terra firme soil; 2. homogeneous primary forest dominated by Monopetalanthus spp.; 3. homogeneous primary forest dominated by Gilbertiodendron dewevrei; 4. heterogeneous primary forest temporarily inundated; 5. heterogeneous primary forest permanently inundated.

Availability of habitat types (class 1-5) along transects (in %) and habitat choice represented by the absolute number (#) or relative proportion (%) of nests found in each habitat type. Habitat types are classified as follows: 1. heterogeneous primary forest on terra firme soil; 2. homogeneous primary forest dominated by Monopetalanthus spp.; 3. homogeneous primary forest dominated by Gilbertiodendron dewevrei; 4. heterogeneous primary forest temporarily inundated; 5. heterogeneous primary forest permanently inundated.

Fig. 8.2 Habitat representation from North to Southx. For abbreviations see legend of Table 8.1.

encounter rate of 1.83 nests per km. The hazard-rate key function was selected by the AIC best fitting model. Regarding the estimate without applying a poststratification, the density is 0.73 weaned individuals/km2 (95% CI 0.29-1.85). After the post-stratification, the estimated density represents 0.49 weaned individuals/km2 (95% CI 0.20-1.21). The encounter rate from within-site transects is much lower than from transects outside the study site (1.6 nests/km for A1-6 versus 2.12 nests/ km for B 1-4). Due to low sample size of the individual transect groups from inside and outside the study area, we abandoned the plan to estimate densities separately for the respective areas.

Marked Nest Count: During the marked nest count survey, we detected a total of 105 nests during 11 repeated transect walks (15 km each) representing a total length of 165 km over a period of 142 days. The half-normal key function was selected by the AIC best fitting model. The estimated density based on it is 0.92 weaned individuals/km2 (95% CI 0.36-2.36) and 1.01 weaned individuals/km2 (95% CI 0.39-2.61) after post-stratification.

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