Sources
Where our facts come from
Every date in an edition is based on a sourced record, with the source printed beside it; where a date is our judgement, the edition says so. Every plant has two institutional sources. This page lists the sources the site and the Austin Edition use.
The Austin windows
- Main egg season, about mid-March to the end of April. Texas Parks and Wildlife; Journey North egg record at Driftwood, 12 March 2025; Monarch Joint Venture, first-generation eggs “from late March through April”.
- Passing through, late September to early November. Texas Parks and Wildlife.
- The busiest three weeks. iNaturalist sightings in Travis County, 2023 to 2025 (also reflect when people are out looking).
- Planting season for milkweed: fall. Native Plant Society of Texas.
Organizations and records
- Texas Parks and Wildlife Department, The Monarch Butterfly. The spring and fall passage through Texas; the milkweed table.
- Monarch Joint Venture, Life Cycle. Stage lengths, sizes and days; first-generation eggs “from late March through April,” behind the end of the Austin egg season.
- Monarch Joint Venture, Migration. The migration and the breeding range.
- Journey North. Dated sightings, such as eggs at Driftwood on 12 March 2025.
- Monarch Watch. Handling caterpillars; habitat size; sexing monarchs.
- iNaturalist. Sightings in Travis County, 2023 to 2025 (these also reflect when people are out looking).
- Lady Bird Johnson Wildflower Center, University of Texas at Austin. Native plants for central Texas; monarch versus queen.
- Native Plant Society of Texas, Bring Back the Monarchs to Texas. When to sow milkweed seed; butterfly weed as a limited host.
- The Xerces Society, Monarch Nectar Plants: Southern Plains (PDF). Nectar plants monarchs use.
- The Xerces Society, Tropical Milkweed: a No-Grow. Why to skip tropical milkweed.
- Texas A&M AgriLife Extension. Local milkweeds; stinging caterpillars.
- Texas A&M AgriLife Extension, Travis County, Fall gardening in a drought? Yes!. Fall as the time to set out perennials, nursery milkweed included.
- Texas Poison Center Network. Poison Help, 1-800-222-1222, from Texas.
- National Capital Poison Center (poison.org), First Aid for Poisonings. First aid on the look, don’t touch plate; when to call 911.
- American Academy of Pediatrics (HealthyChildren.org), Anaphylaxis. Severe allergy signs; epinephrine before an antihistamine.
- MedlinePlus, Caterpillars. Caterpillar stings: rinsing an eye, a wrapped ice pack.
- US Centers for Disease Control and Prevention, Cleaning and Disinfecting with Bleach. Household bleach safety.
- US Census Bureau, 2020 ZCTA-to-county relationship file. How the finder turns a ZIP code into a county.
Hometown Field Guides is not affiliated with any of these organizations. The full register, with retrieval dates and record lengths for every slot, is being moved onto this page from our research files. Plate sources are printed under each plate.