Field Journal 4

Field Journal 4: Social Behavior and Phenology
March 21, 2021
Start time: 9:34
End time: 10:53
Location: Lake Champlain Waterfront, Burlington, VT
Weather: 35 degrees F, 0% cloud cover, SSE wind at 6 mph
Habitats: Lakeshore covering both shallow and open waters, urbanized habitat with sparse trees.

I took a few moments to observe a small group of four Mallards all floating on the lake and traveling in the same direction. in terms of interspecies interactions, it appeared that this species relied on visual cues or soft vocalizations directed between the group. One male would venture off and dabbled down for food. This behavior was observed by another female in the group, who proceeded to travel over to the male and feed there. The rest of the group then followed after visually observing this behavior. This interaction was different then when mallards were observed flying together, where loud vocalizations were heard. It was a bit difficult to discern what these vocalizations may mean, as the small group were only traveling in one direction with no observed physical interaction. However, it could be hypothesized that they were attempting to communicate the direction they wanted to fly, and were trying to keep each member of the group together. The loud volume of the vocalizations may also indicate that they wanted to make their presence known to other mallards in the area.

This interaction was quite different from those of other species, such as the Ring-billed Gull. I was able to observe an interspecies interaction. between two individuals swimming in the lake. There were no attempted interactions between the two. One proceeded to sit in the water looking around, while the other was much more active. It dipped its head into the water, perhaps to feed, and eventually took off flying from the water on its own. Vocalizations were made once in flight, perhaps to find other individuals or make its presence known. I was unable to observe any prominent interactions between two different species, however different vocalizations, such as alarm calls, may be understood between many different types of birds.

Looking at the plumage patterns of mergansers, we can see how the coloration provides a considerable ecological advantage for the species. The male, seen with dark iridescent black and green on its back and white on the underbelly and bottom wings, provides it with camouflage on the water. The darker back and head blends into the dark water surface as seen from a top view, protecting against potential predators The white along the wings may help break up the shape of the bird in rough waters. The white underbelly blends in with the light coloration of the sky as seen from below the surface of the water, helping the bird remain difficult to spot by prey. Females have a much more muted coloration of grey and whites on the body, and a brownish red head. This coloration may help the female camouflage more effectively than the male, allowing her a better chance of survival to protect any offspring or reproductive success of the species.

The plumage of house sparrows that were observed is quite different. Although they exhibit sexual dimorphism, both the male and female have very muted brown and grey plumage. This coloration may help this species camouflage within short shrubbery, bushes, and branches, which is different habitat compared to that of the mergansers. House sparrows also exhibit a slight form of counter shadowing, with underbellies being slightly lighter than the back of the bird, allowing for shadows to make the lighter bottom match the value of the top of the bird. This phenomenon is not as important for the mergansers who spend much of their time on the water, requiring a more stark contrast in coloration between the water and sky.

Returning to the observations of the four Mallards, particular observations were made of a male who explored the area dabbling for potential food underneath the water surface. It was swimming alongside two females and one other male, and proceeded to leave the group by a few feet and dabble, before returning back to the group. this behavior fits into circadian rhythm cycles in a few ways. During the day, metabolic processes increase, accounting for increased activity and feeding behavior. This light provided from the sun has caused the Mallard to be more active and alert, as the pineal gland receives the light and the hypothalamus regulates all metabolic activity through neurotransmitters. When looking at circannual cycles, it can be observed that this Mallard would be in the process of vernal spring migrations to reach breeding grounds. This would require high energy to complete this activity efficiently.

Mini Activity -
Spishing attracts birds for a number of different reasons, and can be really effective at drawing birds out of hiding. It can be most productive in a fairly open area with vegetation that provides cover for different species. This sound primarily attracts small birds, such as Black-capped Chickadees due to curiosity, and other species will often follow the smaller birds check out the situation. Another possibility for why spishing attracts birds is due to defense. The sounds may be interpreted as aggression, as it mimics alarm calls that are often made when a threat is nearby. This results in small birds to flocking together to investigate and drive off the potential threat. Although this method may be effective, it should be used sparingly as it promotes stress in different species. Although defense is the main hypothesis, spishing also resembles the sounds of many insects, potentially attracting insectivores to the area in search of a potential meal.

Posted on March 22, 2021 08:25 PM by acshiers