Blue Jay Observation

The Blue Jay (Cyanocitta cristata)

The blue jay (Cyanocitta cristata) belongs to the family Corvidae and the order Passeriformes (Cornell University, 2015). It is one of the most common birds to be sighted in the United States. It has a range that covers about 2/3 of North America (Johnson, 2011). Blue Jays tend to migrate only over short distances, and have never been observed anywhere south of the United States. Given their wide distribution pattern, many observations relating to their life history and ecology have been made allowing for a better understanding and appreciation of Cyanocitta cristata. Although blue jays have been observed in various habitats, they are most commonly found and observed near oak trees. When examining the location of these oak trees, blue jays are commonly
found at the edges of the forested area that contain the oak trees. The rapid development of and expansion into the habitats of the blue jay by humans has caused the blue jay to adapt to a new non-forested surrounding. They can now be found and observed in both suburban and urban areas where there is a prevalence of bird feeders and oak trees (Kaufman, n.d.). The habitat that blue jays live in can also affect their lifespan. The average lifespan of a blue jay in the wild is approximately 7 years, although the oldest recorded blue jay was found to live for 17 years and 6 months (Johnson, 2011). If blue jays are captured from their habitats and raised in captivity their lifespan can last until they are around 26 years of age. Despite this, the one thing that is common amongst all blue jays is that they reach sexual/reproductive maturity when they are one year of age. Once blue jays, both male and females, reach sexual maturity they undergo sexual photoperiodicity before each mating season. Sexual photoperiodicity is where an organism, in this case the blue jay, has physiological responses involving their reproductive organs in response to the changing amount of sunlight in a day. The research conducted by Thomas Bissonnette in the 1930’s, showed that both male and female blue jays undergo sexual photoperiodicity, but the changes associated with females in order to be ready for mating season occur at a slower rate than the changes associated with males (Bissonnette, 1939). The breeding season for blue jays begins around mid-March and runs through the end of July (Johnson, 2011). Some of the courtship behaviors exhibited by blue jays include aerial chases (where the female is pursued by the male) & the male feeding the female blue jay. Blue jays typically are a monogamous species, where once a female chooses a male to mate with it is a bond for life or until a member of that pair dies (Johnson, 2011). As soon as a female blue jay chooses a mate, both the male and female have to select a site and begin to build a nest.
A factor that has to be considered is the nest’s location and its risk of predation. Research has found that nesting success is not influenced by the nesting site/habitat characteristics but rather by the habitat’s influence on predator distribution (Tarvin & Garvin, 2002). Both the male and female work together to build the nest, and when construction is completed the female lays between 2-7 eggs once per breeding season (Cornell University, 2015). Both parents contribute to incubating the eggs, and feeding the nestlings once they are hatched. The young leave the nest at 21 days and typically reach independence, where they no longer need their mother and father, at the age of 3 months (Johnson, 2011). At maturity, both male and female blue jays have the same coloration pattern. The only way in which one could distinguish between the sexes is to take notice that male blue jays tend to be larger in size. The average weight of blue jays is between 2.3 – 3.84 oz (65 – 109 g) and the average body length is between 8.7 – 12.5 inches (22 – 32 cm) (Johnson,
2011). A factor that is dependent upon the relative success of blue jays and influences their selection of habitat nesting site and survival of their young is the availability of food. Blue jays have a diet that consists of a subsistence of nuts and seeds from trees and shrubs, fruits, grains, and have been known to eat small vertebrates that are dead or have been injured (Cornell University, 2015). In order to obtain their food blue jays employ a number of methods ranging from visual search cues to tool making. Blue jays use both cuing and priming to search for and find prey. Research has shown that the use of these two methods simultaneously in predatory searches interferes with a blue jay’s ability to find prey and it is thus less likely that both methods are employed at the same time in the wild (Goto et al., 2014). When blue jays are selecting which nuts to eat, they will preferentially select those that are small and are more easily ingested (Moore & Swihart, 2006). This tendency for blue jays to prefer smaller nuts has a negative impact on larger trees within the blue jay’s habitat, as the larger trees will not have a high seed dispersal percentage. When food sources are scarce or are hard to reach, blue jays in captivity have been known to use their beaks to construct tools in order to rake seeds closer to their cages (Jones & Kamil, 1973). This tool making behavior has yet to be observed with blue jays living in the wild. Cyanocitta cristata, more commonly known as a blue jay, is a songbird that is prevalent in most of North America. It has several interesting aspects of its life history, such as habitat preference and the fact that once females choose a male they remain monogamous until one or both members die. Despite that the estimated global population of blue jays is 13 million (87% in the United States, 13% in Canada) and that the IUCN lists Cyanocitta cristata as a species of least concern, a blue jay’s habitat should still be respected and conserved. If this is done, it will ensure the continuation of the species, and the enjoyment of bird watchers for many generations to come.