World Migratory Bird Day falls on Saturday, May 9, this year. The 2026 theme set by the international partner organizations — including the Convention on Migratory Species, the African-Eurasian Migratory Waterbird Agreement, the East Asian-Australasian Flyway Partnership, and Environment for the Americas — is Every Bird Counts: Your Observations Matter, highlighting the role of community science in migratory bird conservation. The observance also coincides with the 60th anniversary of the International Waterbird Census.
We want to mark the day by sharing the spring 2026 data from our two monitoring programs that most directly intersect with this work: our pollinator corridor monitoring program, now in its fourth year, and our migratory bird observation program, which we run in partnership with the regional Audubon chapter. The full datasets are publicly available on our open data portal. This post is the layperson summary.
The picture, fairly read, is mixed. There is real reason for cautious encouragement in some of what we are seeing. There is also real reason for concern in other parts of it.
Pollinator corridors: the good news
Our pollinator corridor monitoring program tracks pollinator activity across nine designated corridor sites in our service area. Each site is visited weekly during the active pollinator season (April through October) by trained volunteer observers, who record presence and approximate abundance of seven indicator species groups: native bumblebees, honeybees, solitary native bees, butterflies, moths, hoverflies, and hummingbirds.
The 2026 spring data, covering observations from late March through April 20, shows several encouraging patterns. Native bumblebee observations are up roughly 14% year-over-year across the corridor network. The increase is concentrated in three corridors — Pearson Creek, Eastside Greenway, and the Norton District garden network — where pollinator-specific planting expansions completed in 2024 and 2025 have now matured into producing flowering plants.
Butterfly observations are similarly up, roughly 11% over spring 2025. The species mix is shifting in directions consistent with our regional climate model: we are seeing more observations of species typically associated with slightly warmer ranges, and slightly fewer observations of species associated with cooler historical ranges. We will say more about this in our annual pollinator report in the fall.
Hummingbird observations are roughly flat year-over-year, which is itself a reasonably encouraging signal given regional trends.
Pollinator corridors: the harder data
Two findings from the spring data are less encouraging.
Solitary native bee observations are down 8% year-over-year. The decline is concentrated in two corridors that have had significant adjacent land disturbance — one near a construction site that came online in 2025, another adjacent to a parcel that had its native vegetation cleared without permit last fall. The data here is telling a story our staff field naturalists have been telling anecdotally for months: native bee populations are sensitive to fairly localized disturbance, and once they decline, they recover slowly even after the disturbance ends.
Moth observations are also down, by about 6%, though the moth dataset has larger margin of error than the other groups because evening observation logistics make it harder to standardize.
The composite picture: the corridor strategy is working where the corridors are well-protected and well-planted. It is not, on its own, sufficient against meaningful adjacent disturbance. The implication for policy work is that habitat quality and adjacent land use protection are not separable.
Migratory birds: spring arrival patterns
Our migratory bird observation program, run in partnership with the regional Audubon chapter, tracks spring arrival dates for 23 indicator migratory species across 11 observation sites. Volunteers log first-observation dates, sustained-presence dates, and approximate counts at each site through the spring migration window.
The 2026 spring arrival data, complete through April 28, shows several patterns worth noting.
Earlier arrivals continue. Twelve of the 23 indicator species arrived earlier in 2026 than the rolling 10-year average for that species. Five arrived later. Six arrived approximately on schedule. The pattern of earlier arrivals is consistent with what is documented in regional and continental datasets, and aligns with research linking spring arrival shifts to broader climate trends.
Species composition is shifting. We continue to log occasional observations of species not historically present in our region during spring migration. Two such species — one warbler and one flycatcher — have now appeared in our spring data for three consecutive years. By the conservative definition many ornithologists use, both species are now part of our regional migratory community.
Some species are arriving in lower numbers. Five of the indicator species are arriving in lower aggregate counts than their 10-year averages, with two of those declines large enough to be statistically meaningful. The species in question are ones BirdLife International and other global organizations have flagged as showing decline trends, so our local data is consistent with the international picture. BirdLife's recent reporting notes that 40% of bird species are in decline, threatening flyways, wetlands, food security, and climate resilience.
What the WMBD theme is asking for
The 2026 World Migratory Bird Day theme focuses on community science specifically — the idea that distributed, citizen-collected observations are critical infrastructure for understanding what is happening to migratory bird populations in time to do something about it.
This is not hopeful framing. It is technical reality. Migratory bird populations move across enormous geographic scales, often across thousands of kilometers, encountering vastly different habitat, weather, and disturbance conditions on each leg of their journey. No professional research network can cover this geographic complexity at the spatial resolution that conservation requires. Community science, done well, is what fills the gap.
The international coordination effort that World Migratory Bird Day represents — the UN-backed campaign bringing together CMS, AEWA, EAAFP, and Environment for the Americas — is, at its core, an effort to scale up community-collected observation infrastructure quickly enough to inform decisions while there is still time for those decisions to matter.
We will say more about that broader argument in a separate post.
What you can do this weekend
For community members in our region who want to participate in the day:
Our Audubon partners are running observation events at four locations on Saturday morning. Registration is on our website. No prior birding experience is needed. Binoculars are provided.
The Cornell Lab of Ornithology's eBird platform accepts observations from anywhere, and Saturday is the WMBD Global Big Day — a global coordinated observation effort that contributes meaningfully to the largest-ever single dataset of bird observations. A casual observer with a phone in their own backyard can contribute real data.
Our community pollinator gardens are open for self-guided visits all weekend. The Norton District network and the Pearson Creek corridor are both worth a walk in the next two weeks while the spring flowering is at its peak.
A closing note
The data we are sharing in this post is the product of dozens of trained volunteer observers, several years of consistent methodology, and the patient work of partner organizations whose names belong on every dataset we publish.
It is also, importantly, modest. Nine pollinator corridors and 23 indicator bird species are not a continental sample. The data tells us specific, useful things about the specific places we monitor. The broader patterns require the broader networks that World Migratory Bird Day is coordinating.
If you want to be part of building that broader picture, this weekend is a useful time to start. Saturday will be a good day to be outside. The birds are already moving.
