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In STEM I, each person is responsible for conducting an Independent Research Project, which we will present in February at a science fair. In the class itself, we engage in various reading and writing activities that help us further understand experiment planning and result presentation. To learn more about my project, read the information below.

For my project, I decided that I wanted to look into the structure of bird nests. More specifically, I wanted to look at the relationship between nest architecture and nest strength. To learn more about my project, look at the the Quad Chart above. Having trouble viewing the chart, click here.

Identifying the Relationship between Nest Architecture and Strength

Overview

Previous research suggests that birds place materials in specific parts of their nest depending on the diameter of the materials (Biddle et al. 2018). Research also indicates that the structure of bird nests is strong (Sindhu Nachiar et al. 2023). However, research is yet to be done examining the relationship between the deliberate material placement and the nest strength. My project will look at specific aspects of nest architecture, such as whether the nest has a mud cup, and see how it influences strength. Results indicate that material placement does not have a significant relationship with nest strength. However, the mud cup makes the nest significantly stronger.

Abstract

Past research has demonstrated that the placement of materials within bird nests is deliberate, with thicker materials placed on the outer portions of the nest and thinner materials placed in the inner portions. Bird nests have also been found to have an overall structure that shows promise in enhancing and strengthening man-made structures. Yet, little is known about the relationship between the material placement within a bird nest and the overall strength. To understand this relationship further, I collected nests from the surrounding community to measure four main things: material orientation (steepness of materials), diameter, and placement, and to analyze the relationship between those properties and the nest strength. Results suggest that nests with mud cups are much stronger and suggest that cup length and width have a significant influence on the inclination of materials In addition, there was no significant relationship between orientation and diameter of materials and nest size that influence nest strength. Results suggest mud like materials, such as concrete should be used to improve domes in the real world to make them stronger. In addition, understanding the characteristics that make a nest strong could make it easier to determine how environmental and other such factors may influence a bird’s need for a stronger nest. The hypothesis was that the architecture of the nest has a significant influence on the strength of the bird nests.

Graphical Abstract

The above picture is a graphical representation of the abstract for my project. Having trouble viewing the chart, click here.

Research Question

How do the diameter, orientation, and location of the materials, as well as size and mud cup of a bird nest influence the overall load strength of the nest?

Hypothesis

It is hypothesized that there will be a significant relationship between nest architecture and strength.

Background Infographic

The picture above is a visual representation of the background for my project and the knowledge gaps that led me to my research question.

Background

Past research suggests that material placement in bird nests is deliberate and is determined based on structural properties, such as diameter (Biddle et al. 2018). However, these studies have failed to look at how these material choices influence the structure of the nest as a whole. In addition, the structure of bird nests has the potential to enhance man-made structures, such as hanging structures (ie. a hanging chair )(Sindhu Nachiar et al., 2023). Despite the overall structure of the nests being strong, as well as the birds deliberately placing their materials in specific regions of the nest, there is yet to be research examining the relationship between this deliberate material placement, or other aspects of the nest architecture for that matter, and the strength of the nest.

Procedure Graphic

The above picture is a visual representation of the steps I took to complete this project.

Procedure

Part 0- Acquiring Nests: I acquired nests from members of the Northborough-Southborough community in late October.

Part 1: Measuring Nest Size: There are five key measurements that were used to understand the shape of the nest: the width, length, height, cup length, and cup height. The width was chosen as the widest part of the nest that ran through the center of the cup and was measured from the top of the nest. Next, the length was measured perpendicular to the width, running through the center of the cup as well. Then, the height was measured from the table where the nest was placed to the highest cluster of sticks (not including any solo stray sticks ). Next, the width and length of the cup were measured. They were measured in the same fashion as the overall width and length, except that the width of the cup was measured along the same line as the width of the nest. The same follows for the measurement of cup length.

Part 2: Measuring Material Orientation: To measure the angle of inclination of the sticks, a photo was taken of the nest. Next, the cardboard square was used to rotate the nest by ninety degrees, and another photo is taken of the nest. This process was repeated for the four sides of the nest. Once this was completed, all photos are imported into the FIJI image editing software. In the software, the average inclination of the sticks above the horizontal was measured.

Part 3-Measure Nest Strength: For strength measurement, the Vernier Structures and Materials Tester was utilized. The nest was first positioned on the top of the tester so that the nest is face up. Then, the U-bolt pulls down on the nest and produce a force versus displacement graph in the Vernier Graphical Analyses software, which is used to calculate the bending rigidity of the nest

Part 4-Nest Dissection: To determine the material placement within the nest, the materials in the nest were sorted based on what position of the nest they were in: the top outer nest, the bottom outer nest, or the cup. Next, I used a digital caliper to measure the diameter of the materials within each section of the nest.

Analysis

Overall, the rigidity of the nests with mud cups are much stronger than those nests that do not include mud cups. It was found through further analysis that the mud cup has the greatest influence on the strength of the nest. Following the nest strength, cup width and cup length also had a significant correlation with the overall strength of the nest (.770 and .832, respectively). The diameter of materials within the nest as well as angle of inclination did not have a significant correlation with the nest strength. In addition, through analysis using a multiple regression, the model proved to be insignificant, suggesting no significant overlap between specific architectural features and the nest rigidity.

Discussion/Conclusion

In terms of statistical significance, this data suggests that nest architecture, specifically material diameter and angle of inclination do not lend themselves in any particular way to making a nest stronger. This suggests that materials are chosen and placed in the way they are for reasons other than strength, such as comfort or insulation. However, the results indicate that mud cups are much stronger, suggesting the idea that if birds have the environmental need for a stronger nest, a mud cup would be the optimal choice. Future research necessitates analysis of more nests. This is in part due to statistics involved in the creation of this project. With more nests, statistical testing would be more representative of the population, thus getting a better understanding of how the nest characteristics influence nest strength. In addition, future research can be done analyzing what birds have created nests with mud cups and what their ambient environment is like. This will help to identify why birds would have the necessity to create stronger nests, which will help gain a greater sense of what environmental factors drive birds to prioritize certain characteristics of their nests (ie. Strength, comfort, camouflage, etc.). In addition, the results of my project bear a greater need to identify what the leading reason is for placement of materials, because of the results suggesting they are not placed in the locations they are in for strength. It is essential to understand why placing stronger materials in the outer parts of the nest and weaker materials in the inner parts of the nest remains a pattern within many bird species (Biddle et al., 2018). Finally, future work could be done analyzing the “optimal” characteristics of domes and to analyze whether concrete domes are stronger than steel rod alternatives.

The goal of this project was to gain greater insight into the inner workings and construction patterns of birds and to understand what patterns and features of nest architecture have the strongest influence on the nest strength. To answer this question, data regarding nest size, angle of inclination of materials, diameter of materials, and placement of materials was collected, as well as data on the nest strength. Then, statistical testing, namely correlation tables and linear regression models were utilized to understand the relationships between nest strength and the individual characteristics within the nest architecture. The results have shown no particular significance between nest architecture and strength, except for that of having a mud cup, which will make the nest much stronger. Understanding the world around us is crucial, for it gives us as human a better connection to nature. In addition, nests are a miraculous feat of animal engineering that humans can stand to learn from, so by learning what they use for what reasons can be used to apply to man-made structures, and thus elevate our structures, one by one.

References

Bhosale, Y., Weiner, N., Butler, A., Kim, S. H., Gazzola, M., & King, H. (2022). Micromechanical Origin of Plasticity and Hysteresis in Nestlike Packings. Physical Review Letters, 128(19), 198003. https://doi.org/10.1103/PhysRevLett.128.198003

Biddle, L. E., Deeming, D. C., & Goodman, A. M. (2018). Birds use structural properties when selecting materials for different parts of their nests. Journal of Ornithology, 159(4), 999–1008. https://doi.org/10.1007/s10336-018-1571-y

Biddle, L., Goodman, A. M., & Deeming, D. C. (2017). Construction patterns of birds’ nests provide insight into nest-building behaviours. PeerJ, 5, e3010. https://doi.org/10.7717/peerj.3010

Harvard John A. Paulson School of Engineering and Applied Sciences. (2025, April 8). How do bird nests stay together? Researchers unravel entanglement between stiff, straight rods. https://phys.org/news/2025-04-bird-stay-unravel-entanglement-stiff.html#google_vignette

Jessel, H. R., Aharoni, L., Efroni, S., & Bachelet, I. (2019). A modeling algorithm for exploring the architecture and construction of bird nests. Scientific Reports, 9(1), 14772. https://doi.org/10.1038/s41598-019-51478-1

Lombardo, M. P. (1994). Nest Architecture and Reproductive Performance in Tree Swallows (Tachycineta bicolor). The Auk, 111(4), 814–824. https://doi.org/10.2307/4088813

Sindhu Nachiar, S., Anandh, S., Yegasainathan, N., & Kowsalya, M. (2023). Shape optimization of hanging structure using the concept of Biomimics.Materials Today: Proceedings, 93, 46–53. https://doi.org/10.1016/j.matpr.2023.09.164

Street, S. E., Jaques, R., & De Silva, T. N. (2022). Convergent evolution of elaborate nests as structural defences in birds. Proceedings of the Royal Society B: Biological Sciences, 289(1989), 20221734. https://doi.org/10.1098/rspb.2022.1734

February Fair Poster

The pdf above is my poster that I presented at the February Science Fair. Having trouble viewing the pdf, click here.

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