A Study in the Behavior of Swans, Final 1

The Swans show off their feeding strategy in this Quicktime Video

This topic submitted by Amanda Fort, Lauren McGraw, Wendy She ( fortam@miamioh.edu ) on 12/11/98 .



Introduction

"The trumpeter swan is the largest species of North American waterfowl," with white feathers and black legs and feet (Ross 35). When viewed up close, a thin orange-red line can be seen on the bottom part of their bill. They can weigh between 21 and 30 pounds, with a wing span over seven feet. In addition to the trumpeter swan, there are two other species, all of which are usually confused with one another. The major differences between the three species of swans are their size, call, and migration. The trumpeter swan is nearly twice the size of the tundra swan, has a deep, sonorous call, and either is non-migratory or migrates small distances. The tundra swan weighs approximately 15 pounds, has a high whistling call, and migrates long distances between the summer and winter months. (Trumpeter Swan, Wildlife Species Information) The mute swan can be identified as having a black and orange bill with a bulb on the top while the bills of trumpeter swans are smooth. The mute swan also has a typically S-shaped neck with its bill pointed downward, while the trumpeter swan holds its neck vertically and its bill horizontally. (Making a Successful Comeback)
In this lab, we will be concentrating on the behavior of the trumpeter swans in the Western pond. The behavior of trumpeter swans is as complex as ours is; however, it is probably more difficult to figure out. Many studies have been done to determine more effective breeding strategies, how to preserve their precious habit, and their fascinating behavior in general. All these studies are in an effort to keep the few populations of trumpeter swans alive, well, and regenerating. It is said that today, "the trumpeter swan is considered one of the classic conservation success stories" (Ross 36). In 1933, the trumpeter swans were close to extinction with only 50 breeding in the United States, and 77 in Canada. They are a success story because of all the research done to aid us in helping them; for we'd know nothing if we did not give the time and energy to find out. Today there are about 16,000 trumpeter swans belonging to three main populations: the Pacific Coast Population, the Rocky Mountain Population, and the Interior Population. These three populations breed and winter mainly on the western coast of the United States and Canada, with the Interior Population originating from the mid-western United States. Roger Schlickeisen, President of Defenders of Wildlife, comments that the "usual work [in recovery] involves trying to prevent losing a species or habitat. We're too often losing something, but here we're trying to get ahead of the curve by restoring something. We're trying to bring back a magnificent species of wildlife with an important role in [many areas] for the benefit of future generations."
Along those lines, studying the behavior of the swans in Western pond offers the possibility of encompassing many things. Perhaps one day the pond becomes contaminated and the swans must be moved; what information may then be helpful in finding a suitable environment for the swans? This is one situation in which gaining and understanding a knowledge base of the swans is important for Miami University as well as other organizations, who may be holding onto swans. Through a series of experiments, extensive observation and collective data, we hope to study the behavior of the swans regarding three of their prominent instincts. The three main behaviors we will document include their feeding habits, grooming patterns, and swimming inclinations. While observing these we will also take into account the time they spend in and out of the water.
While many lab experiments can be presented quantitatively, we find it more beneficial and representative of our research to display our observations qualitatively as well. Studying the behavior of living things lends to a more descriptive explanation of observations as well as a numerically sound data table. Numbers can tell us only so much about how the swans behaved when approached, where they spent the most time, and what behaviors they perform most and varied descriptions of those behaviors.
By conducting this experiment, we plan to gain a conclusive knowledge of how the swans in Western pond behave as opposed to that of swans in the wild based on information obtained from books and published studies. This research will be interesting to us and capture our attention because we only have predictions as to the behavior of these swans, and in order to make a final report analyzing our collected information; we have to gather a knowledge base of these swans. Our hypotheses for this project concern their behavior as compared to that of swans in the wild. We are going to assume that the swans here in Western pond behave basically the same, as do swans in the wild. In relation to the data we will be collecting as well as our preliminary observations, we predict that the swans will spend the majority of their time in section 1, and swimming. And because we have already noticed that the birds are very synchronized in their behaviors, we will predict that the time they each spend actually performing them will be similar.
This research, when related to the larger question, will give us an idea of how similar wild swans are to those held in captivity, in their common behaviors. This research will also make evident the differences in the behaviors of the Western swans that are held in captivity as opposed to wild swans who can migrate and such. The swans in the Western pond have adapted to their new environment because they are forced to stay there. Over time, they will forget some of their normal behaviors like hunting for food or migrating to different areas during the different seasons. Some of their normal behaviors will stay the same though, like feeding, grooming and swimming.


Description of Common Behaviors

Feeding: During the spring, summer, and fall months swans feed on leaves, tubers, and roots of aquatic plants at depths up to 1 m which they reach by dipping their heads and necks, or by up-ending. During the winter months they feed on the roots of those aquatic plants which can be found.
The swans feet are very important when feeding, constantly being pumped up and down over roots and plants to create a current of water which stirs up the mud and releases them from the ground. The large size of the feet also aids in balance when the swans up-end to feed.
The swans here on Western feed on primarily the same foods that those in the wild feed upon, however, they are given regular rations of dried corn year round, and in the winter are given lettuce. They also enjoy the occasional treat of bread from tourists. An article entitled "Gaining Ground: A Swan's Song" by Drew Ross described the winter supplementation of swans diets in the Yellowstone National Park population. These swans, also "feeding on leaves, stems, roots, and tubers of submerged, floating, and emergent plants", were given wheat and poultry feed during the winter in order to help ensure their health and survival (Ross 36).
One main problem caused by the continual feeding of swans occurs when large craters where the birds' bill has uprooted plants are created. This can be destructive to an area's vegetation.
Grooming: Swans, like us, groom themselves regularly. They may groom each other also, by picking at each other's feathers to remove dirt and bugs. When the swans groom themselves, they tend to come out of the water, ruffle their feathers, and on occasion spread their wings as if they are stretching.
Swimming: Of course we all know that swans swim, but do they swim in order to feed, for pleasure, or because the water is where they feel most at home? We defined swimming as time spent on the water when feeding or grooming was not taking place.


Class Integration:

We will begin our explanation of our lab in class by giving a short introduction of what it is that we are trying to do and accomplish. This will include information on swans, descriptions of their behaviors, and our hypothesis. It will also introduce our thoughts as to the relevance of our research. A brief video taped by Amanda will then be shown so that the students will gain a better understanding of two of the three behaviors in which they will later be observing themselves. And following this we will explain our procedural and observation methods, as well as our data tables. (Attached)
In order to integrate the class into our research we are going to conduct one in-class observation session where each group will be assigned a section of the pond to monitor. This is in order to make sure that they understand how we went about collecting data, because they will then be assigned, according to their groups, a specific time to go and observe the swans and collect data. We will then use this data in our final evaluation and analysis.

Observation Schedule and Assignments
1) Group 1 (Water Striders) - between 8 and 11 AM
2) Group 2 (Fish) - between 11 AM and 1 PM
3) Group 3 (Kepler's Law) - between 2 and 4 PM
4) Group 4 (Erosion) - between 4 and 6 PM


Materials
- stop watch or timing device
- data table
- spray paint
- tape measure
- video camera


Methods

1) We first sectioned off the pond into four sections.
2) The boundaries of each section were then marked on the grass with spray paint so that we are able to tell from land the approximate dividing lines between sections in the water.
3) Next, we recorded brief descriptions of the environments of each section. Attached is a rough map of the pond sectioned off with environmental descriptions accompanying each.
4) Then we went about filling out the data tables, observing which sections the swans were in and what behaviors they are exhibiting and timing the occurrence of each behavior.
Observation Methods:
1) Go to the pond and wait for the swans to get use to you for about 2-5 minutes.
2) Use the data sheet for which section they are in and time what behavior(s) they are doing in that section. For example, time how long they are feeding in section 1, section 2, etc.
3) When they move to a different section use the chart from that section and observe the swans as before.
4) Continue to do this for 20 minutes


Other Research Done and Information Found

Conover, Michael R. and Kania, Gary S. "Impact of Interspecific Aggression and Herbivory by Mute Swans on Native Waterfowl and Aquatic Vegetation in New England." The Auk Jul 1994: 744-748.

Summary:
Biologists launched this experiment of Mute Swans in Connecticut to study the impact of the increasing population of free-ranging Mute Swans on native waterfowl and plant life. Observations were made from the shore in order not to disturb the natural behaviors of the swans. Researchers concentrated on their behavior around other birds, owning to their aggressive nature. Along these lines, they also tried to establish whether there were sexual differences and seasonal variations in aggressiveness.
The experiments used to scientifically record the behavior patterns and herbivory effects of waterfowl are addressed in this article. The results of the given experiments are outlined, including observations and statistical information of the amount of sampling done and observations made. There are also various charts sited which list results largely by the sex of the specific swan, including the types and numbers of other native waterfowl which were being attacked, the seasons in which the most attacks occurred, the responses of the various waterfowl to these attacks, and the types of plants that were grazed and ungrazed by the swans in various seasons.
Biologists also summarize this experiment citing what was learned about the Mute Swans from this experiment and concerns and questions ignited by their research.

Cooper, James A. and Henson, Paul. "Trumpeter Swan Incubation in Areas of Differing Food Quality." Journal of Wildlife Management Oct 1993: 709-716.

Summary:
Analysis of intraspecific variation in the incubation patterns of trumpeter swans in relation to age and body condition, nest site selection, variability in environmental foods, and geographic location. These patterns ultimately can be used to investigate the effects of age and experience on reproductive success in geese. This article outlines the experiment conducted in 2 breeding areas where food and quality differ. Methods for observation and gathering data are discussed, along with the results of the information gathered. Tables and graphs are provided to show the percentages of time female swans spent feeding on emergent, submerged, and surface vegetation, of the general activity of the female swans during incubation, and the amount of incubation recesses grouped by length female swans took. Discussion of findings and calculations and management implications are also included.

Delacour, Jean. The Waterfowl of the World, Vol. 1. London: Country Life Limited, 1954.

Summary:

This book described the general habits and captivity of swans. More importantly, it taught me that mute swans migrate in search of food and open water. They feed mainly on waterweeds and look their best only on the water. Swans build big nests usually near swamps or reed-grown water.

Delacour, Jean. The Waterfowl of the World, Vol. 2. London: Country Life Limited, 1954.

Summary:
This book described swans as a very popular waterbird. It gave me a general description of mute swans and some of their body characteristics. They seem to wag their tails pretty often. The mute swans, as their name implies, have a call that is not as loud as other species. That is the main difference between this species and others, such as the trumpeter, whose call is one of the loudest. These aggressive birds come across as very violent by moving both feet at once.

Johnsgard, Paul. Handbook of Waterfowl Behavior. New York: Cornell University, 1965.

Summary:
This book taught me about the actions of mute birds, and their general, as well as sexual, behavior. When the swan's neck feathers are ruffled, it indicates aggression, and a slimming of the feathers is a sign of fear. Wing flapping is also used as a threat display.

Madge, Steve and Hilary Burns. Waterfowl. Boston: Houghton Mifflin Co., 1988.
Summary:
This book was most helpful in describing many of the resources I needed. I read about the description, parts, and measurements, as well as the habitat and distribution of the mute swans. The adult swans are all white and their young are brownish-gray. The habitat of swans centers around bodies of water like lakes, pools, lagoons, bays, and rivers. They are a very widespread breeding bird.

Nicholas, James D. and Bart, U. "Annual Survival rates of Adult and Immature Eastern Population Tundra Swans." Journal of Wildlife Management Jul 1992: 485-494.

Summary:
Two of the primary objectives for this experiment on tundra swans was 1) to estimate annual survival rates for swans using capture-recapture-resighting data obtained over the last 2 decades and 2) to test the hypothesis about age- and sex-specific variation in annual survival of tundra swans. Researchers were interested in finding out if the survival rates for tundra swans were similar to those of other species of swans.
Methods for gathering data are discussed, including neckbanding and legbanding, and the capture-recapture-resighting technique. Through these processes the sex, weight, age, etc. of each bird studied was recorded and resightings were done to estimate the number of swans which remained, thereby satisfying the objectives for the experiment.
This article contains statistical data representing the neckband retention rate and the survival rate in relation to the age and sex of the swans. Models were also used to test a series of hypotheses about sources of variation in the neckband retention rates and estimates in the survival rates after initial calculations were done. Informational tables included relate to the goodness-of-fit tests and the likelihood ratio tests, both having to do with neckbanding and the capture-recapture-resighting technique. Also included in the article are the research implications and the discussion of what was learned and obtained from the research.

Paca, Lilian. The Royal Birds. New York: St. Martin's Press, 1963.
Summary:
From this book I learned about the mating and many characteristics of swans. A swan mates for life with only one other mate. They never seem to age and stay gleemingly white, strong, and beautiful.

Ross, Drew. "Gaining Ground: A Swan's Song." National Parks Mar/Apr 1998: 34-39.

Summary:
The flock of trumpeter swans, which inhabit the waters of Yellowstone National Park, was in grave danger of becoming non-existent. Recovery programs for these birds have been established, however, it is a long and slow process. Many of these programs have involved feeding the birds and augmenting their habitat in order to make survival and reproduction more fruitful. Researchers soon found out there were problems with this plan which ultimately led to overcrowding, which in turn could possibly cause the swans to die. Because of this occurrence, new ideas were discussed, and new plans enacted. Today the swan population in Yellowstone is being watched closely and is regulated with the help of the captive-breeding program.

Silverin, Bengt. "Reproductive Adaptations to Breeding in the North." American Zoologist Jun 1995: 191-202.

Summary:
This article explores how swans, by altering their responses to day length, food availability, access to a mate and temperature, breed successfully in northern latitudes. Because the changes in the photoperiods of higher and lower latitudes differ, the swans must physiologically adapt to the changes in the environment so that the processes of reproduction won't be disturbed. This paper contains graphs that represent the breeding periods of different species of swans, the gonadal cycles in great tits exposed to different temperatures and light regimes, and the genous testicular and LH cycles in two newly established startling populations.


Results

In the end, we chose to accept our hypothesis and assume that the swans in Western Pond behave basically the same as swans in the wild according to the three behaviors studied. The data obtained from our observation of the swans we plugged into StatView and were given a range of graphs and statistics in which we will explain and evaluate. See attached graphs.

Graph 1
This graph describes the three behaviors of the swans and when they were most likely to perform these behaviors. Time, the y-variable, is computed in seconds, and the three behaviors are listed on the x-axis. From this graph we found that:
The swans fed more during the afternoon hours than morning hours, feeding about 3000 seconds in the afternoon and only 500 in the morning. We attribute this to the fact that they are regularly fed by the university around 2:30 everyday and that they are more inclined to perform other behaviors in the early morning.
The swans groomed more in the morning than in the afternoon, grooming about 5000 seconds in the morning hours, and only about 1500 seconds in the afternoon. We feel this is a natural inclination that they not only have, but we, as humans possess as well.
The swans swam more during the afternoon than in the morning, swimming about 6500 seconds in the afternoon, and only about 3000 in the morning. This could be because they spend most of their time in the morning grooming themselves; however, they tended to generally be more active during the afternoon hours.

Graph 2
This graph describes the feeding patterns in relation to the big and small swan. From this graph we are able to tell which swan performed more of a behavior than another did, or just how synchronized they are. From this graph we found that:
The swans feed for about the same lengths of time during each interval, feeding at the most for about 600 seconds and the least for 20 seconds. When it comes to feeding the swans appear to be very sychonized and perform many of the behavior swans in the wild do such as pumping their feet to loosen plants, etc. We also noticed that when it came to feeding on the grass and corn left by the university, the larger swan (male) usually came out of the water to feed first and only after he returned to the water would the smaller (female) come out to feed.
For example, during intervals 1, 4, 5, 7, and 8, the swans feed for the same amount of time ranging from as little as 20 seconds to as much as 600 seconds. During intervals 2 and 9, the big swan feed for more time than the small, and during intervals 3 and 6, the small swan feed for more time than the big swan.

Graph 3
This graph shows the swimming patterns in relation to the big and small swan. From this graph we found that:
The swans are pretty much the same in their habits. For example, during intervals 1, 4, 5, 7, 8, 9, 10, 11, 12, 13, and 16 they swam for the same amounts of time ranging from about 100 seconds to 700 seconds, with the small swan almost always following the big swan.

Graph 4
This graph shows the grooming patterns in relation to the big and small swan. Unlike the other behaviors, we found the swans to be somewhat synchronized in their grooming tendencies. From this graph we found that:
The swans tended to each groom at different intervals, with the small swan grooming during 7,8, and 9 for up to 100 seconds. We believe the reason for this is that the small swan would usually groom the big swan more often than the big groomed the small.

Graphs 5 - 7
All these graphs show the varied amounts of time that the swans spent doing each behavior. For all three behaviors, both swans spent an average of 120 seconds doing each.

Graphs 8 - 9
These graphs show the amount of time the swans spent in and outside the water. At most, the swans would spend 20 minutes outside the water. Usually this was to feed on the grass and corn, or groom on the mud bars in the pond.

Graphs 10- 13
These four graphs show the temperature ranges, times of day, weather conditions, and section distributions in which our data was obtained. We feel that the swans spent more time in section 1 (A) because of the shallow water, which is more conducive to feeding, and the various disturbances in the other sections.

In addition to the graphs, we found the average times the swans spent doing each of the three behaviors, the time spent in and outside the water, and the temperature. From these averages, we can assume that the swans tend to swim more that they groom, and groom more than they feed. They also seem to spend more time in the water than out of the water.
The standard deviation of each of the behaviors tells us how much, +/- whatever the value may be, our data varies. For instance, The standard deviation for the temperature is about 6. This means that, when added to and subtracted from the mean, that the majority of the temperatures varied between 46 and 58 degrees. In the rest of the categories, the standard deviation is quite large. We attribute this not only to the obviously widespread data collected, but from collection error that may have occurred with the class observations as well as our own. The difficulty of accurately timing the swans in each section is great, and therefore must be done often over a long period of time in order for the data to be more precise and conclusive. That would also aid in the reduction of our percentage of error in each of the categories, with our highest being for their time spent out of water.


Conclusion

Our project may not seem the same as other groups', but our study had the most changes. At first, we could not decide what to do. Eventually, we developed a hypothesis on the eating or feeding habits of the swans and how they reacted toward colors. This hypothesis and experiment was similar to the
fish group, where they were testing fish's reactions toward colors. In our initial attempts to carry out this experiment we tried to throw colored balls on to the pond and see how the swans would react to them. Unfortunately, they did nothing. So we had to develop yet another plan of attack along with a new hypothesis. Our new hypothesis was based on the swans' behavior in nature. This experiment shared some similar motives with the water strides group. They were studying how nature affected the water strides with the purpose of finding out where they most preferred to live, while we were testing how their nature of seclusion has changed the way the swans behave in the pond as opposed to in the wild. Just as the erosion group was testing the after effects of nature, we were testing the after effect of seclusion on the swans. And like the Kepler group, we were also trying to prove, again, the known facts on the specific ways that the swans will feed, swim, and groom.
Of course, there were many different ways we could approach this study. First, we could concentrate on only one of the swan's behaviors like feeding, swimming, or grooming. Secondly, we could study their living habits in the water or out of the water. And thirdly, we could study their behavior toward humans. Within our study, there were more questions we needed to consider. We didn't have sufficient time to take into account the temperature changes, noise of the street, or the mating season. If given more time, we could've studied their changing behaviors during many weather conditions and through the different seasons. We would've been really interested to see how the swans' behave during their mating season and how they protect their young.
Unfortunately, based on the nature of our data and observations and that of which we found from other sources, we could not do a T-test to compare our data to the already known data, but we did compare the pond's swans' behaviors to that of the wild swans' behaviors. In general, our swans have not been greatly effected by being held in captivity. Contact with humans is limited, other than the daily visits from the groundskeeper or the few students that stop by to see them. In conclusion, we decided to accept our hypothesis, in that their normal habits concerning the three behaviors we studied: feeding, swimming and grooming, were not greatly affected by their seclusion from other swans and their captivity here on Western pond.


Bibliography

Ross, Drew. "Gaining Ground: A Swan's Song." National Parks Mar/Apr 1998: 34-39.
"Making a Successful Comeback: The Reintroduction of the Trumpeter Swan." Aldo Leopold Chapter, Society for Conservation Biology. http://www.ies.wisc.edu/partners/alc-sch/wiscbiod/swan.html

"The Swans Have Landed." Migratory Bird Project. 19 December 1997. http://www.defenders.org/pr121997.html

"Trumpeter Swan." Canadian Wildlife Service: Hinterland Who's Who. 10 November 1997. http://www.ec.gc.ca/cws-scf/hww-fap/swan/swan.html

"Trumpeter Swan, Wildlife Species Information." The United States Fish and Wildlife Service. http://www.fws.gov/r9extaff/biologues/bio_swan.html

"Trumpeter Swans: A Regal Release." Minnesota Zoo. http://www.wcco.com/partners/mnzoo/tswan.html

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