The eclectic background music ranges from old-school jazz to Michael Bolton. There are about a dozen birds to pet, photograph, and even perch on your hand or head. The species include barn owls, eagle-owls, scops and tawny owls. On our visit there were several hatchlings, and an impressive, hulking Eurasian eagle-owl who turned out to be just two months old.
The most popular bird is a northern white-faced owl, a cute and friendly little critter without a leash. He'll sit on your arm and pose for pictures before suddenly flying off to his perch, sending a staff member running to bring him back. The system is streamlined and efficient.
New visitors receive a short talk on bird handling before entering the bird room, have their hands disinfected, and then are free to perch on a bar stool or interact with the owls. You can claim your drink at any time, and the bank of vending machines has a live-streaming screen that shows your drink being made inside the bowels of the machine, as it happens, live! Apparently this is popular photo op with tourists.
Twenty subplots were distributed along the sides, and one was at the center of each 50 x 50 m plot. For the analysis, we used mean values of leaf litter depth per 50 x 50 m plot. We registered canopy opening four times one in each direction of the four cardinal points in each corner and at the center of the 50 x 50 m plots.
The raw values recorded in the field were then multiplied by 1. In the analysis, we used the mean values of the percentage of canopy opening per plot. In the 50 x 50 m plots, we counted all forest logs on the forest floor, which were longer than 1 m and with diameters greater than 20 cm. The total number of logs recorded per plot represented an index of forest log abundance in the analysis. All snags with diameter at breast height DBH above 20 cm were counted inside the 50 x 50 m plots.
All trees with DBH greater than 15 cm were counted in the 50 x 50 m plots. The reason for measuring only trees with diameter at breast height above 15 cm is that they are large enough for owls to perch, rest or nest. For each owl species, we ran Pearson correlation matrix analysis to test for correlations among the forest structure components independent variables.
The effects of the forest structure components on the occurrence of owls were evaluated with models of logistic regression using the SYSTAT 8.
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For this part of the analysis we have included all 60 records of two owl species Lophostrix and Glaucidium and 30 records of the other species Megascops. To analyze the effects of each forest structure component on the abundance of each owl species, we constructed multiple linear regression models, also using the SYSTAT 8. Only those 8 km transects which have minimum of one owl were included in the analysis, therefore 16 transects were considered for Lophostrix and Megascops and 17 transects for Glaucidium.
To verify potential problems of residual analysis in multiple regressions we used a graphic method called partial residual plot, available in the statistical program "R". The same program was also used to evaluate multicolinearity. Therefore, to verify possible linear relationships among predicting variables, we estimated the variance inflation factor which calculates the level of multicolinearity FOX The leaf litter depth ranged from 1.
The mean percentage of canopy opening was 9. The mean altitude was The mean distance to the nearest stream was The results of the correlation among all of these variables are presented separately for each owl species in tables I , II , and III , and those significantly correlated were not included together in the same regression models see below. Effects of forest structure on the occurrence and abundance of L. Lophostrix cristata was widely distributed in the reserve and throughout most of the eighteen 8 km transects Fig.
The occurrence of L. The abundance of forest trees was significantly correlated to the abundance of logs see Tab. I , thus these variables were not included in the same regression model together with the others forest components. We then run a separated analysis for the abundance of forest trees and found out no significant effects of this variable on L. The abundance of L. However, there was a positive relationship between the abundance of L.
As stated before, the abundance of forest trees was significantly correlated to abundance of logs Tab. Effects of forest structure on occurrence and abundance of G. Glaucidium hardyi also showed ample spatial distribution in the Ducke Reserve Fig. The occurrence of G. However, there was a positive and significant relationship between the occurrence of G.
Northern Spotted Owl - Washington Forest Protection Association
The abundance of forest trees was significantly correlated to abundance of logs and abundance of snags see Tab. II , therefore, it was not included in the same regression model together with the others forest components. We then run a separated analysis for the abundance of forest trees and found out no significant effects of this variable on G. We recorded 93 individuals of G.
None of the forest structure components have significantly affected the abundance of the G. Because the independent variables tree abundance and distance to the nearest stream were significantly correlated with the others as showed by the results of Pearson correlation matrix Tab. II , we used them in two separated simple linear regression models to evaluate their effects on G.
None of them influenced the abundance of G. Effects of forest structure on the occurrence and abundance M.
Most of the 54 individuals of M. Since the independent variable leaf litter depth was significantly correlated to abundance of forest trees and abundance of snags, and altitude was correlated to forest canopy opening Tab. III , their effects on M. The occurrence of M. Note that for this owl species tree abundance and distance to nearest forest stream were not significantly correlated see Tab. Therefore, these variables were included together in the same regression model.
However, leaf litter depth was correlated with abundance of trees and snags, and altitude was correlated to forest canopy opening see Tab. Therefore we used leaf litter depth and altitude in separated models, and found out that the occurrence of M. The abundance of M. Leaf litter depth was significantly correlated to abundance of forest trees and snags, so it was altitude correlated to canopy opening Tab.
III , they were not included in the same regression models with the others forest components Tab. There were positive relationships between the abundance of M. There was also a negative relationship between the abundance of M. However, the abundance of M. Finally the abundance of M. The results of this study indicate that the environmental heterogeneity produced by isolated or combined effects of forest structural components can influence the occurrence and abundance of some owl species in Central Amazon forest.
However, not all owl species were affected in the same way. The crested owl Lophostrix cristata occurrence was affected only by the abundance of snags, the Amazon pygmy owl Glaucidium hardyi occurrence was affected by the canopy opening, and M. On a larger spatial scale, the relief seems to be important for owl occurrence and abundance. Both L. Owls generally are opportunistic birds in the use of the resources available, and their frequent use of areas with high abundance of snags may be a consequence of the use of dead or alive trees in their activities BUCHANAN et al.
At Ducke Reserve we found that the abundance of both L. However, the use of snags for nesting is not always favorable. The authors suggested that nest predators visit snags more often when they are searching for food. Number of fallen trees was important for the mottled owl Strix virgata , and canopy height for the black-and-white owl S. The calling activities of the three owl species were associated with the moon phase, and were also correlated with the season of the year.
In our study area, G. VI , Fig.
Some owls' species may move to other areas when local conditions are limited. At Reserva Ducke, the higher abundance of M. This species often hunts flying from a perch to the ground. Because areas of shallow litter tend to have less debris dead twigs and leaves , the detection and capture of preys on the ground would be easier. At Ducke Reserve, M. We believe that this owl species is more frequent in areas of higher tree density because they tend to use more closed and shaded areas and tall trees for nest construction and roosting MARKS et al.
In fact, vegetation structure seems to be more important for some owl species to select spots for rest and breeding rather than feeding. The long-eared owl Asio otus builds its nests in areas with closed canopy, and this behavior seems to reduce predation on their juveniles BULL et al. The availability of areas for shelter and rest during the day could be another reason why M. Individuals of this species use closed and dense forests more often probably because they are more able than other species to fly maneuvers in areas with many obstacles.
Individuals of M. This is not a particular preference of this species only. In areas of accentuated forest floor inclination, the canopy of a given tree may be closer to the ground than those from plateau areas, and this may help the owl to surprise and, in a short flight, catch more ground preys in these areas.
However, this might not be a behavior showed exclusively by tropical owls. The availability of preys and their density may affect density and habitat use by many raptors, including the spotted owl Strix occidentalis CAREY et al. In the Amazon forest, KILTIE found that rodents hide seeds and fruits near forest logs, and often return to the same spots to recover them.
The increase in rodent movements around forest logs may attract the attention of owls, which may use the areas more often than those without logs because of the ease of detecting and capturing prey there. Individuals of G. The use of areas near forest streams by this species could be related to capture of prey. Forest canopy along the streams is more open and may help long flying and gliding movements for locomotion and hunting. At the Reserve, a relatively high number of small, semi-aquatic and terrestrial rodents, birds, frogs, lizards, and other potentials prey are associated with aquatic environments.
Finally, our results indicate that the environmental heterogeneity of the forest through its forest structure components at the local and regional levels large spatial scale can be determinants to explain the occurrence and abundance of owl species in a given area.
Wildlife & Ecosystems
We also found that the way habitat structure affects owls was species dependent. Although the forested area of city around the reserve is decreasing every year due to the rapid urban growth of Manaus, we think that the populations of the three owl species seem to be relatively intact. Lophostrix cristata may be one of the least known among the species of owl recognized in the world, and in the Amazon region, it is associated with mature forest terra firme forest for roosting and nesting.
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Forest fires aren’t so bad for spotted owls
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