This is a provisional and certainly incomplete list of the Odonates (Dragonflies and Damselflies) of Skyline Open Space Preserve. There are certain additional species that no doubt occur in the reserve as I have seen them nearby: Pantala flavescens, Pantala hymenea, Cordulegaster dorsalis etc. As well, this list serves as a starting point for determining the entire fauna of Odonates found the Mid-peninsula Open Space district set of preserves. Some fieldwork needs to be done in other sites to gain a clearer understanding of what species are widespread in the reserve system, and which may be found only at Skyline Open Space. Alpine Pond and Horseshoe Lake are great habitats for Odonates, and as ponds and lakes are rare in the higher elevations of San Mateo County so they may have a richer odonate fauna than other sites, yet this remains to be determined. Several species of damselfly and dragonfly are only known from San Mateo County from Skyline Open Space Reserve, but this is certainly a factor of the time that has been spent observing at this site over others.
Damselflies - Zygoptera
- California Spreadwing Archilestes californica. Sept 20 - Oct 22.
- Uncommon. 9/20/2002 One male photographed (digital).
This appears to be the first confirmed record of this species in the county, and Skyline Open Space remains the only place it is known from in the county.
- Spotted Spreadwing Lestes congener. Sept. 2, 1995.
- Status? Need to visit more in September time frame.
- Common Spreadwing Lestes disjunctus. July 14, 2000.
- Status? Need to visit more in July - August time frame.
- California Dancer Argia agrioides. May 29 - July 14.
- Vivid Dancer Argia vivida. June 14 - October 22.
Enallagma species (below) are notoriously difficult to identify. Netting and releasing can be used to census these species.
- Boreal Bluet Enallagma boreale. May 29, 2002.
- Status unclear.
- Tule Bluet Enallagma carunculatum. May 29 - July 14.
- Northern Bluet Enallagma cyathigerum. May 29, 2002.
- Status unclear.
- Arroyo Bluet Enallagma praevarum. May 29 - Sept. 2.
- Common???? Status unclear.
- Pacific Forktail Ischnura cervula. May 29 - Sept. 20.
- Western Forktail Ischnura perparva. June 12 - Sept. 2.
- Exclamation Damsel Zoniagrion exclamationis. Early spring 2001.
- Desert Firetail Telebasis salva. Sept. 2, 1995.
Only known site in county? Have not seen them again since 1995.
Dragonflies - Anisoptera
- Blue-eyed Darner Aeshna multicolor. May 29 - Sept. 20.
Notes: The similar California Darner, Aeschna californica is likely here as well. It flies earlier, and perhaps some of my earliest records of A. multicolor may pertain to this species. Two individuals observed on May 29, 2002 at Horseshoe Lake may have been A. californica.
- Walker's Darner Aeshna walkeri. June 13 - Sept. 20.
- Common, main flight season is later than A. multicolor.
- Common Green Darner Anax junius. June 12 - 14.
6/12/2000- Female noticed egg laying, Alpine Pond.
- Western Pondhawk Erythemis collocata. May 29 - June 14.
Only known site for this species in the county, Skyline Open Space reserve. It is likely more widespread than presently known.
- Eight-spotted Skimmer Libellula forensis. May 29 - Sept. 14.
- Common Whitetail Libellula lydia. May 29 - June 13.
- Flame Skimmer Libellula saturata. June 12 - 14.
- Blue Dasher Pachydiplax longipennis. June 12 - Sept 20.
- Variegated Meadowhawk Sympetrum corruptum. Sept. 20, 2002.
Migrates through county, in some periods of the year may be quite common, particularly late September into October. May eventually find that for periods of time this is a common species in the reserve.
- Cardinal Meadowhawk Sympetrum illotum. May 29 - Sept 2.
- Striped Meadowhawk Sympetrum pallipes. Sept 2 - Oct 22.
This may be the only known site for the species in the county?
- Black Saddlebags Tramea lacerata. Sept. 20, 2002.
9/20/2002 Pair mating observed on Alpine Pond.