Analyzing a Scientific Article and a Project on Bird Beaks

The first part of my assignment was to read a scientific article and answer some questions about it:

1. What 3 reactions do shorebirds usually have to the presence of humans?

a. Watching the humans

b. Walking away from approaching humans

c. Flying over to an undisturbed section of beach

2. What is the potential consequence of these reactions?

Abandonment of the sections of beach with humans, including foraging areas

3. What does foraging mean?

Foraging is searching for food.

4. How many beaches were studied and where were they located (general area)?

13 beaches in Ventura County, CA

5. How often was data collected? What affected the number of days between surveys?

a. once per month

b. Tides

6. What 3 things were counted during surveys?

a. Shorebirds

b. People

c. Dogs

7. Over what period of time did the entire study take place?

June 1994-May 1997

8. What were the total counts of birds, humans, and dogs during this time?

Birds: 22,087, from 23 different species

Humans: 3,629

Dogs: 528

9. Define the following:

Mean: the average, derived by adding up all the numbers and then dividing by the number of terms

Standard Deviation (SD): a number that indicates the variance between two values

Range: the difference between the lowest and highest values of a data set

10. What assumption did the researchers make about the relationship between shorebird abundance and the presence of humans/dogs?

That the number of shorebirds would be directly affected by the number of humans and dogs.

11. Was this assumption correct? Why or why not?

It was not correct. There are other factors that could affect the result, including the physical characteristics and conditions of the habitat and the availability of prey.

12. What were some reasons other than human/dog use that might affect the number of shorebirds on a particular beach?

Physical characteristics of the habitat, such as the slope of the beach and the height of the waves, as well as the availability of prey.

13. Which beach had the largest mean number of shorebirds? Of humans? Of dogs? Which had the least for each? Looking at the entire data set for Table 1, does there appear to be a correlation between the abundance of shorebirds, humans, and/or dogs? Explain your answer.

Ormond 1 has the largest mean number of shorebirds; Marina beach has the largesr number of humans, and Silver Strand has the most dogs. Hobson beach had the fewest birds; Deer Creek had the least amount of people, and Ormond 2 and 3 had the fewest dogs. There do seem to be fewer shorebirds at beaches with lots of humans.

From the fact that there were more shorebirds on beaches with few people, I would infer that there is a correlation of some sort. However, there is a lot of variation in the data, and there could be more than one reason for the correlation. Correlation isn't causation.

14. Looking at the data for the 3 Ormond Beach sites, what did the researchers think about the possible relationship between shorebird abundance and human presence?

The researchers concluded that the population of birds at the Ormond Beach sites was due to a consistently low human population.

15. Did the researchers find that the number of shorebirds was impacted by the presence of humans/dogs? Was this the result they expected when they started this study?

The researchers came to the conclusion that the presence of humans affected the shorebird population, while the number of dogs had little effect, which surprised the researchers due to the dogs being frequently observed chasing the shorebirds.

16. What problems with their approach do the researchers admit to?

Counts were conducted only once a month, from Monday through Friday. Meaning that there was no accounting for weekend fluctuations, or for an increase in people on holidays.

17. What would you have done differently to create a more scientifically accurate study?

I would conduct counts once per week, and alternate between counting on weekdays and weekends. Also counts should be conducted at the same time of day, to avoid inconsistencies.

The second part of my assignment was to do a project showing the difference is the beaks of birds with different feeding strategies.

Surface skimmers fly right above the surface of the water and stick their elongated lower jaw under the surface of the water, snapping up any fish unlucky enough to be in their path.

Examples: Black skimmer (Rynchops niger); African skimmer (Rynchops flavirostris.)

A scything beak is used by wading birds to pick small prey items out of the mudflats.

Examples: Pied Avocet (Recurvirostra avosetta) American Avocets (Recurvirostra americana.)

Aerial fishers have a sharp, spear like beak, perfect for quickly striking and stabbing their prey.

Examples: Pied Kingfisher (Ceryle rudis) Great Blue Heron (Ardea herodias.)

A pursuit fisher actively chases after its prey, instead of ambushing it. The bill is wider than an aerial fisher's, and often has a hook at the end for grabbing slippery fish.

Examples: Great Cormorant (Phalacrocorax carbo); Flightless Cormorant (Phalacrocorax harrisi.)

Pelicans are famous for dip netting. Dip netters swallow a large gulp of water, then drain off the water, leaving behind fish, small crustaceans, and other such food items.

Examples: Brown Pelican (Pelecanus occidentalis); American white pelican (Pelecanus erythrorhynchos.)