Field Observation 7

I made these field observations on Wednesday, April 22 from 11:30 am to 2:00 pm in Basel, Switzerland. The temperature was approximately 68 degrees Fahrenheit and the weather was clear and sunny. These observations were made at a park called the Rheinpark which is next to the Rhein River, a wide river with a strong current that runs through the middle of the city. The park is upstream from the main city center and is right next to a very large dam. There are less buildings/roads near the river here and there are more green spaces for wildlife. For example there are many small grassy areas and trees/bushes running along side the banks of the river.

When I arrived at the park I could hear many different bird songs, although it was often difficult to pinpoint the exact location of these songs. For example, I heard an interesting chorus coming from a dense cluster of bushes. It sounded like 2 birds singing together so I thought that it was possible that it could be a duet being sung by breeding partners. Unfortunately, I wasn't able to see the birds that were singing. I think that it was likely that many of the House Sparrows, Common Chaffinches, and other small birds that I saw were nesting in some of the dense bushes lining the edge of the park. I could hear many chirps coming from the bushes, and they would be very well protected from the people walking by.

Further upstream, past the dam, I saw two Great Cormorants sitting on a floating dock in the water. I also saw two Eurasian Coots, a Gray Wagtail, and several ducks further in the distance that I could not identify. On my way back I came across a mother Mallard and 8 ducklings at the mouth of a small tributary river which flows into the larger river. Interestingly, there were 3 male ducks also in the same area and there wasn't any sign of aggression or territoriality between the ducks. This could be because there were ample resources available to the ducks (people often throw food to them), meaning that there was no reason to fight over resources. The mother duck did not have any nest that I could see, however I noticed that she kept her ducklings in the shallow water of the tributary river, rather than bringing them out into the rapid main river, which might be dangerous for them.

Lastly, later that afternoon, I walked through the park by my house (Schützenmatt Park) and noticed that there was one particular tree, that was tall and with wide, strong branches that had at least 10 Carrion Crow nests! The crows were loudly cawing back and forth to each other. I thought it was quite interesting that they all chose the same tree for their nests. I noticed another tree, of the same species, in the park that also had a similar number of crow's nests. It could be that this type of tree simply has the best branches for carrying nests, as they are wide, sturdy and up high. This would mean that the crows simply have to fight over who gets the bests nesting spots in the tree (which could be why they were making so much noise!). It is also possible that the there is an evolutionary advantage to nesting in groups, for example by increasing safety from predators.

Publicado el 22 de abril de 2020 a las 09:23 PM por abreyo