MassWildlife has kicked off an innovative project using state-of-the-art radio tracking technology to monitor the survival and migration of wood thrushes, aiming to boost conservation strategies for forest-nesting birds. This effort, launched in partnership with the U.S. Fish and Wildlife Service (USFWS), various state wildlife agencies, Worcester Polytechnic Institute, and other conservation groups, focuses on understanding the movement patterns and annual survival rates of these birds, which have been declining for decades, according to an article on Mass.gov.
Wood thrushes, known scientifically as Hylocichla mustelina, have seen a population drop of over 50% since 1970. Recognized as a Species of Greatest Conservation Need by MassWildlife and as a Species At-Risk by the USFWS, these migratory birds are now at the center of a broad study designed to collect crucial data across their breeding and migration routes, including in Massachusetts and their overwintering sites in Mexico and Central America.
This project leverages the Motus Wildlife Tracking System, a global automated radio telemetry network capable of tracking small flying animals like birds and bats. Motus stations are spread worldwide, with a high concentration in New England and the mid-Atlantic. MassWildlife and its partners have recently deployed 50 Motus stations across the region, including a 10-station line across Massachusetts from the Berkshires to Cape Cod.
In June 2024, MassWildlife biologists attached Motus transmitters, each weighing just over a gram, to 25 adult wood thrushes near existing Motus stations. The transmitters emit signals every 16 seconds and last approximately 500 days. Biologists captured the birds using mist nets, banded them, determined their age and sex, and recorded measurements before fitting them with transmitters secured with elastic loop harnesses. The devices, designed to rest on the birds’ lower backs, are lightweight and do not affect their natural behavior or migration.
Data collected from these birds has shown high survival rates through the summer, with nearly all tagged wood thrushes beginning their fall migration between mid-September and early October. Multiple Motus stations have detected the birds during their southbound nocturnal flights, with ongoing updates available on Motus’ website.
According to Drew Vitz, MassWildlife’s State Ornithologist, “The project has progressed very well so far. We expect the results to provide important new insights into the movement and survival of wood thrush in Massachusetts and beyond.” The plan is to tag more birds in 2025 to gather two years’ worth of data before analyzing the outcomes.
This project comes at a critical time, as a recent study in Science reported that bird populations in the U.S. and Canada have decreased by three billion since 1970. With many bird species facing long-term declines, studies like this are essential for shaping effective conservation policies to reverse population losses.
