Madison House Finch Populations 2021 & 2022
The monitoring of invasive species is critical in the efforts to conserve native species that are threatened by them. The house finch (Haemorhous mexicanus) is a very common passerine bird that can be found all throughout New Jersey. Originally introduced for the purpose of being a house pet, advertised under the flashy name of “Hollywood” finches, they now pose a threat to a multitude of native species. They compete with native birds such as the purple finch and the goldfinch, as well as the non-native house sparrow. House finches are highly adaptable, finding suitability in a range of habitats from deserts to woodlands, as well as urban and suburban areas like the borough of Madison. Examining the population trends of the house finch from 2021 to 2022 helps Madison to be informed on how to address this bird’s impact on other species, while following the guidelines of NJ Fish and Wildlife’s Wildlife Action Plan. In addition, it points to what the potential cause of the shift in their population may be attributed to.
Analyzing population shifts is an essential part of understanding the level of threat that an invasive species poses onto other organisms. The map displays the density of house finch populations provided by eBird data in 2021 and 2022.
This dataset considers the populations of multiple invasive bird species in New Jersey. Species included were the mute swan, house sparrow, house finch, European starling, and the brown-headed cowbird. Throughout New Jersey, there was an average percent decrease of 76.79% from 2021 to 2022 from all these species. When looking specifically at the house finch, Madison followed this declining trend. Brighter and more vibrant coloration on the map indicates a higher density while lighter, more transparent coloration indicates lower density. Then green data points are for the populations found in 2021 and purple data points are for 2022.
Understanding the cause of shifts in wildlife populations aids in a broader understanding of how to respond to the change, and whether it should be hands on or hands off. With such a drastic decline in house finch populations, as well as a multitude of other invasive species, it could be considered that the analysis of data that is utilized by citizen science is the most influential factor at play. However, there was an increase of “eBirders”, and therefore reported sightings, by an addition of 97,000. The most likely contributor to these immense drops in populations is to a pathogenic disease, called avian influenza. U.S. Fish and Wildlife has created the Interagency Steering Committee for Avian Influenza Surveillance in Wild Migratory Birds to monitor and ensure the biosecurity of domestic and wild birds. Continuing to report information on bird populations from both citizens and workers within the wildlife sciences is essential to the conservation of bird species.
About the Data Source:
The range of the House Finch in 2021 and 2022 are a product of “eBird” observations in the state of New Jersey. The observations are verified through an array of automated data filters to determine the species, count, location and date of the sighting. The automated filters are developed by volunteers and are regularly updated.
Data on House Finch populations in New Jersey has demonstrated a stark decline in population numbers between 2021 and 2022. The data from this source does not extend to before 2021.
Municipal boundaries of the borough of Madison were established by the New Jersey Office of GIS (NJOGIS).
