(Bellarmine College, Louisville, Kentucky)

Aaron Glasscock

G.W. Johns

Keri Owen

December 11, 1998

Birds have always been of interest to the human population. Birds have served as the source of inspiration to flight, sources of myths, and as companions. Competition has also been a large part of human existence, it is not only an aspect of life it is also an interest to man. With this in mind, it was the interest of this group to study birds in a setting that would be conducive to observing the interactions and competition among birds. This group set out to determine the degree of competition found in birds, both intra- and inter-species.

Purpose:

To observe and record the interactions among birds, both intra- and inter-species competition, through the observation of the feeding behaviors in birds.

Method:

The group researched and determined a location to observe the feeding habits in birds. The location decided on was located in Fern Creek, a suburb south of Louisville Kentucky. It was decided to establish two separate feeders, with different feed, in order to observe the two different types of competition, intra- and inter-species. One feeder (designated feeder "A") was placed hanging off a tree branch. Feeder "A" hung approximately five feet from the ground. Feeder "A" was filled with mixed seed, big and small, in order to attract several different species of birds. A second feeder (designated feeder "B") was established approximately 150 feet from feeder "A". Feeder "B" was placed on a railing approximately five feet above the ground. Feeder "B" was filled with one type of seed. The seed was small and intended to attract finches. Feeder "B" was established to specifically study intra-species competition.

Feed was placed in both feeders and maintained for approximately one week before observations were made. After the initial week, observations were made during four different periods throughout the day for approximately one month. The four different observation periods were in the morning, noon, afternoon, and early evening. Feed was maintained in the feeders during the month. The number of birds, both in total numbers and the numbers within a specific species were observed. The different species present were observed and noted. The behavior of the birds was also noted.

The data collected during the month was averaged to correspond to data representing one day.

Discussion:

Three different species of birds were observed in the study. The three species were finches, doves and blackbirds.

Figure 1 represents the feeding of birds at different periods through the day vs. the number of birds observed feeding. The frequency of feeding was observed to increase through the day. The frequency of feeding peaked during the afternoon hours. A drastic fall in feeding frequency was observed during the evening hours. More finches were observed feeding than any other species during all four of the time periods studied. The blackbird was not observed in the morning, appearing only in the last three time periods of the day.

The increase in feeding frequency throughout the day was correlated to the increase in temperature. The increase in temperature was speculated to cause an increase in activity of the birds, thus directly effecting the increase in feeding frequency observed in the bird species.

The number of finches feeding in comparison to the number of the other two species could be attributed to the area in which the observations were made. However, we attributed the large number of finches feeding compared to that of the doves to their dominance and assumed position in the hierarchy of the local community.

Figures 2 and 3 represents the location of feeding in relation to the feeder (feeder "A") in the absence of the black bird species. The figures also represent the location of the different types of species feeding in relation to each other. These diagrams are an illustration of the inter-species competition observed and to an extent the intra-species competition.

Figures 2 and 3 consist of two circles. These circles represent the boundaries of what we deemed as two key feeding rings. The area enclosed by the inner circle is what we called the primary feeding ring and the area between the circles is what we designated the secondary feeding ring. The primary feeding ring consisted of the food that was dropped or kicked out of the feeder. The secondary feeding ring consisted of the feed that was kicked, blown, or moved from the primary ring to the secondary feeding ring. The feed in the secondary feeding ring was deemed to be of lesser quality and less desirable than that in the primary feeding ring or the feeder.

Figure 2 represents that the finches assumed the primary feeding location on the feeder. Speaking in relation to only finches, a definite sense of intra-species competition was observed. It was observed that the same several birds seemed to maintain the feeding position atop the feeder while the others were relegated to feed on the ground. Most of the finches feeding on the ground were forced to feed near the border of what we called the primary feeding ring. It seemed as if a dominance hierarchy was pre-established and followed. Feeder "B" offered better observations of the intra-species competition. This will be discussed later.

Figure 2 also represents the inter-species competition. Again, the finches were observed to dominate the feeding atop of the feeder. The more dominant doves were observed to feed inside the primary feeding ring. The more dominant doves were observed to maintain better feeding positions than the less dominant finches, feeding on the better seed. In the same sense the less dominant doves were observed to hold less desirable feeding spots than the less dominant finches. This relationship showed that the finches were overall more dominant than the doves, but the more dominant doves showed dominance over the less dominant finches.

Figure 3 is a diagram that represents the same feeder, feeder "A" in the presence of the black bird species. Referring to figure 3 it is quite apparent that the most dominant species overall is the black bird species. It was observed that when the black bird species were present that all other species would disperse. The black bird clearly showing its dominance in this situation. It was interesting to observe two of the more dominant doves move from the primary feeding ring just outside the secondary feeding ring with the arrival of the black birds. This was interesting for several reasons. One, they were the only birds to remain in the immediate area. The second reason this was interesting is that the two doves remained outside the secondary feeding ring for only several seconds (approximately 30 seconds) then flew from the immediate area.

Feeder "B" was an interesting study into intra-species competition. The feeder was designed to attract only finches. This was accomplished by using a type of bird seed specifically designed for finches. During peak feeding periods, anywhere from 10 to 20 birds would be in and near feeder "B." The dominance of some individuals was obvious. Those that were dominant were frequently seen chasing the less dominant individuals away from the feeder not allowing them to feed until they (the dominant individuals) were complete. Some individuals were observed that seemed to understand the hierarchy and just waited on the fringes of the area until it was their turn to feed. Other individuals observed tried to test their dominance. Often times these individuals would fly into the feeder and try to establish dominance which upset those already present at the feeder. On several occasions this caused a small skirmish between several individuals.

Conclusion: