Some Notes on Young Desert Horned Larks
| Autor: | Leon Kelso |
|---|---|
| Rok vydání: | 1931 |
| Předmět: | |
| Zdroj: | The Condor. 33:60-65 |
| ISSN: | 1938-5129 0010-5422 |
| DOI: | 10.2307/1363310 |
| Popis: | From September 1, 1928, to July 30, 1930, the writer had under observation a small area of level waste land within the city limits of Aurora, Colorado. The Desert Horned Lark (Otocoris alpestris leucolaema) was found here throughout the year. Four nests of this bird were found in the spring and summer of 1929, and one in the spring of 1930. Some observations made upon the birds are thought to be worth recording. The area concerned was rectangular in shape, extending 700 yards north and south by 500 yards east and west. It was bordered on the south by Montview Boulevard, a busy thoroughfare running from Aurora west through the adjacent city of Denver. In the east-central part of the area was a small colony of prairie-dogs (Cynomys ludovicianus) numbering about eight individuals. The Environment.-The Horned Lark is closely associated with the plant life of the environmerit in which it lives. Therefore the following notes on the vegetation of the area are presented. The nomenclature used is that of Coulter and Nelson's New Manual of Rocky Mountain Botany. The identifications have been checked from material in the herbarium of the University of Wyoming. Common names are not available for many of the species, so none is given. The short-grass association covered most of the north and central portions of the territory, about 70 per cent of the ground. This is the principal association throughout the range of the bird studied. It prefers this for roosting and nesting. The dominant species were grama grass (Bouteloua oligostachya) and slender fescuegrass (Festuca octoflora). Subdominant species were Muhlenbergia gracillima, Chrysothamnus plattensis, Opuntia polyacantha, and Gutierrezia sarothrae. Less frequent species were Allium nuttallii, Leucocrinum montanum, Buchloe dactyloides, Viola nuttallii, Lepidium apetalumn, Hedeoma hispida, Plantago purshii, Gaura coccinea, Aristida longiseta, Erysimum asperum, Phellopterus montanus, Eriogonum effusum, and Gilia micrantha. There were also on bare ground two species of low moss and two species of lichens. Leaves of Bouteloua oligostachya comprised 60 per cent or more of the material in each nest. The ruderal association occurred on ground that recently had been cultivated, in an old yard and along the road in the southern end and in the northwest corner. This type of vegetation covered about 10 per cent of the area in all. Here the larks preferred to feed, for it provided many seeds in the winter and supported much insect life in the summer. The young larks were often escorted here on account of food and better protection while yet unable to fly. Different plant species were dominant in different parts of the association. These were Helianthus annuus, H. petiolaris, Iva xanthifolia, and Salsola pestifer. Subdominant species were Bromus tectorum, Sitanion elymnoides, Chaetochloa viridis, Schedonnardus paniculatus, Poa pratensis, Kochia scoparia, and Chenopodium album. Less frequent species were Amaranthus retroflexus, A. blitoides, Lappula erecta, Norta altissimna, Malvastrum coccineum, Sophia pinnata, Cryptanthe crassisepala, Aster hebecladus, Artemisia aromatica, and Centaurea picris. The wheat-grass association was found in irregular scattered patches in the western and southern parts of the territory. In the winter the grass dies down, leaving open bare ground with many small depressions between the tufts in which |
| Databáze: | OpenAIRE |
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