Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this data was produced as part of the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. This study is described in the publication listed in the larger work citation of this metadata record. In 2011 through 2013, I mapped territories of male Grasshopper Sparrows and calculated territory size. A 95% kernel density estimate was used to calculate territory size.

Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this data was produced as part of the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. This study is described in the publication listed in the larger work citation of this metadata record. In 2011 through 2013, I recorded the number of eggs in each nest, once laying had ceased

Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this data was produced as part of the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. This study is described in the publication listed in the larger work citation of this metadata record. In 2011 through 2013, I recorded the number of eggs in each nest, once laying had ceased

Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this data was produced as part of the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. This study is described in the publication listed in the larger work citation of this metadata record. In 2013, the dimensions (length and width) of 1–2 eggs were measured in a randomly selected subset of nests as soon after the nest was found as possible.

Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this data was produced as part of the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. This study is described in the publication listed in the larger work citation of this metadata record. In 2013, the dimensions (length and width) of 1–2 eggs were measured in a randomly selected subset of nests as soon after the nest was found as possible.

Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this data was produced as part of the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. This study is described in the publication listed in the larger work citation of this metadata record. This dataset contains the identity of the plant species under which the nest was constructed.

Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this data was produced as part of the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. This study is described in the publication listed in the larger work citation of this metadata record. This dataset contains the identity of the plant species under which the nest was constructed.

Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this data was produced as part of the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. This study is described in the publication listed in the larger work citation of this metadata record. In 2011 through 2013, I took nest measurements within a week of nest failure or fledgling. However, in 2011, the first year of nest monitoring, I measured 17 nests more than 7 days after nest completion. Measurements included: nest opening, inside diameter, inside depth, nest height, orientation of nest opening, length of tunnel, and nest concealment.

Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this data was produced as part of the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. This study is described in the publication listed in the larger work citation of this metadata record. In 2011 through 2013, I took nest measurements within a week of nest failure or fledgling. However, in 2011, the first year of nest monitoring, I measured 17 nests more than 7 days after nest completion. Measurements included: nest opening, inside diameter, inside depth, nest height, orientation of nest opening, length of tunnel, and nest concealment.

In 2010-2013 a variety of measurements were taken from grasshopper sparrows captured as part of the study described below and referenced in the larger work citation of this metadata record. Measurements include age, sex, wing length, weight, and exposed culmen length. Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this is the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. Specifically, I found that ammolegus males generally weighed less than other subspecies (16.0 ± 0.8 g), but with intermediate exposed culmen length (11.6 ± 0.5 mm) and wing chord length similar to the other two migratory subspecies (62.7 ± 1.5 mm). Territory size for ammolegus was 0.72 ± 0.37 ha, with some variation between sites and among years, possibly indicating variation in habitat quality across spatial and temporal scales. The return rate for ammolegus males was 39.2%. Nest initiation for ammolegus was early to mid-July after the monsoons had begun. Domed nests were constructed on the ground, primarily under native bunch grasses, and frequently with a tunnel extending beyond the nest rim, with nest openings oriented north. Clutch size was 3.97 ± 0.68, with no evidence of Brown-headed Cowbird (Molothrus ater) nest parasitism. Extreme climate factors in the arid Southwest may have affected the life history and morphology of ammolegus as compared to other subspecies, influencing body size and mass, culmen length, breeding phenology, and nest orientation. Other geographic variation occurred in return rates, clutch size, and nest parasitism rates. The baseline data for ammolegus obtained in this study will inform future taxonomic and ecological studies as well as conservation planning. Comparisons of ammolegus morphometrics with those of other subspecies will assist field biologists in distinguishing among subspecies where they overlap, especially on wintering grounds.