Nature’s Notebook

Connecting People with Nature to Benefit Our Changing Planet

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Nectar Connectors

Project Background

We are seeking observers to learn about the flowering timing of nectar sources for monarchs and other pollinators! Pollinators are an essential part of our environment - they ensure the reproduction of 85% of the world's flowering plants, and over two-thirds of our crop species. Many threats, including habitat loss and use of pesticides, threaten these pollinators.

common milkweed, Photo: Jason Hollinger via Wikimedia Commons

One of the best-known butterlfies in North America is the monarch butterfly. Monarchs are renowned for their complex life cycle, which takes them on the longest-known migration distance for insects. 

Due to this complex, long-distance migration, the dietary needs of monarchs are complex. The nectar that they rely on to fuel their flight comes from a diverse suite of flowering species that occur across a large geographic area. Changes to these food sources, through habitat loss, pesticide use, or climate change, can be costly to monarch populations, as well as to the many other pollinators that rely on these same species for their dietary needs.

See what we learned from this campaign in 2017. 

Join us!

You can learn about these important nectar sources for monarchs and other pollinators by observing flowering of nectar plants in your own backyard, a nearby park, or other location you frequent! Your reports will help resource managers like the US Fish and Wildlife Service to better understand where and when nectar sources are available for monarchs and other pollinators across the United States so that they can take necessary steps to conserve and promote habitat for these pollinators.

The campaign focuses on 53 species of nectar plants in 16 genera. These species have been identified as important nectar sources for monarchs and other pollinators by the Xerces Society, Monarch Watch, the US Fish and Wildlife Service (USFWS), National Audubon Society's Hummingbirds at Home and Plants for Birds programs, and the Community Greenways Collaborative. These genera include:

  • Milkweeds (Asclepias spp.)
  • Blazing stars (Liatris spp.)
  • Asters (Symphyotrichum spp.)
  • Goldenrods (Solidago spp.)
  • Joe Pye Weed (Eutrochium fistulosum)
  • Lanceleaf coreopsis (Coreopsis lanceolata)
  • Lupines (Lupinus spp.)
  • Bee balm/bergamot (Monarda spp.)
  • Black-eyed Susan (Rudbeckia hirta)
  • Coneflowers (Echinacea spp.)
  • Sunflowers (Helianthus spp.)
  • Prairie clovers (Dalea spp.)
  • Thistles (Cirsium spp.)
  • Cardinal flower (Lobelia cardinalis)
  • Golden Alexanders (Zizia aurea)
  • Baccharis (Baccharis halimifolia)

See the full list of species by searching The Plants and Animals page, filtering for the Nectar Connectors Campaign under Plant Type. 

How to participate

1. Select one (or more) species to track from the list of species. To see which species are available in your state, go to The Plants and Animals page, and filter for your state and Nectar Connectors Campaign (under Plant Type). 

2. Join Nature's Notebook. If you haven't already, create a Nature's Notebook account. See our specifics of observing if you need more details on getting started.

3. Sign up to receive our Nectar Connectors campaign messaging (in the right sidebar of this page - you may need to scroll back up to see it). You will receive messages approximately every 4-6 weeks during the growing season, providing early results, encouragement, observation tips, interesting links, and campaign-specific opportunities. Don't miss out!

4. Take observations. We invite you to track leaf out in your plants ideally 2-4 times a week in the summer and fall when plants are flowering. We are especially interested in flowering phenophases, though you are welcome to report on leafing and fruiting as well.

5. Report your observations. As you collect data during the season, log in to your Nature's Notebook account and enter the observation data you recorded. You can also use our smartphone apps to submit your observations! 

Download a handout about the Nectar Connectors Campaign.

2017 Results for Nectar Connectors 

In 2017, 206 observers reported on Nectar Connectors species at 135 sites. The most observed species were common milkweed (Asclepias syriaca), New England aster (Symphyotrichum novae-angliae), and butterfly milkweed (Asclepias tuberosa).  

The map below indicates the sites where you reported on Nectar Connectors species this year. The color of the dots indicates when the average first date of open flowers was reported at that site, with earlier dates in blue and later dates in orange. 

In the Midwest and Upper Northeast, onset of flowering generally occurred in the summer months. In the Southeast and Western United States, onset of flowering occurred in both the early spring and late fall. This may reflect the combination of spring, summer, and fall flowering plants in these regions. 

Nectar Connectors map of sites with open flowers

The number of individual plants with open flowers generally followed a similar pattern in different regions across the country. Peaks in the number of plants with flowers occurred in June and again in August for the Midwest, Northeast, and Southeast. These multiple peaks may be due to the composition of species that typically flower in different seasons. 

Nectar Connectors num indiv plants flowering

Many observers answer a secondary question about the intensity to which the phenophase occurred on their individual plants. For the open flowers phenophase, this is the percent of flowers that are open.  In the Southeast, Midwest, and Northeast, the peak in the number of plants with 95% or more flowers open occurred in July. For the Western United States, there was no obvious peak. This pattern may reflect growing season length, as we see the strongest peak in July in the two regions which have the strongest seasonality - the Midwest and Northeast. 

Nectar Connectors peak in flowering

What does this mean for monarchs? In the Eastern United States, monarchs migrate north from Mexico in the spring, and subsequent generations eventually reach the northern United States and Canada in the summer. Monarchs then make their migration back south in the late summer and fall. This year, perhaps due to the warm weather that extended into fall, monarchs were spotted in the northern part of the country much later than in an average year. The Western population follows a distinct migration pattern and generally winters in coastal California. 

Nectar Connectors reports indicate that generally flowers were available for monarchs at locations along their migration route at the time monarchs would need them in a typical year.  As we see more unusual seasonal climate such as early springs and late autumns, your data will help us to better understand how these nectar sources are responding. We need data from more sites to fill in the data gaps and determine if sufficient flowers are available where and when monarchs and other pollinators need them the most.

See more results from 2017 data collection on our Nectar Connectors dashboard.