auk (version 0.8.0)

process_barcharts: Process eBird bar chart data

Description

eBird bar charts show the frequency of detection for each week for all species within a region. These can be accessed by visiting any region or hotspot page and clicking the "Bar Charts" link in the left column. As an example, these bar charts for Guatemala list all the species (as well as non-species taxa) that have been observed in eBird in Guatemala and, for each species, the width of the green bar reflects the frequency of detections on eBird checklists within the region (referred to as detection frequency). Detection frequency is provide for each of 4 "weeks" of each month (although these are not technically 7 day weeks since months have more than 28 days). The data underlying the bar charts can be downloaded via a link at the bottom right of the page; however, the text file that's downloaded is in a challenging format to work with. This function is designed to read these text files and return a nicely formatted data frame for use in R.

Usage

process_barcharts(filename)

Value

This functions returns a data frame in long format where each row provides data for one species in one week. detection_frequency gives the proportion of checklists in the region that reported the species in the given week and n_detections gives the number of detections. The total number of checklists in each week used to estimate detection frequency is provided as a data frame stored in the sample_sizes attribute. Note that since most months have more than 28 days, the first three weeks have 7 days, but the final week has between 7-10 days.

Arguments

filename

character; path to the bar chart data text file downloaded from the eBird website.

See Also

Other helpers: auk_ebd_version(), auk_version(), ebird_species(), get_ebird_taxonomy()

Examples

# example bar chart data for svalbard
f <- system.file("extdata/barchart-sample.txt", package = "auk")
# import and process barchart data
barcharts <- process_barcharts(f)
head(barcharts)

# the sample sizes for each week can be access with
attr(barcharts, "sample_sizes")

# bar charts include data for non-species taxa
# use category to filter to only species
barcharts[barcharts$category == "species", ]