The latest number is now the lowest since records began in 1982. The farthest flung red knot populations spend the winter at the southern tip of South America, in Tierra del Fuego. Locations of active Motus receiver stations (white dots with black outlines), and the northern migratory trajectories of 48 adult Red Knots tagged in South Carolina during April and May (20172019) and Florida in March 2019 and detected during northbound migration. Baker, A. J. et al. Red Knots were captured in predominantly single species flocks with cannon nets, removed immediately, and placed in holding cages for processing. Red knot tracking studies are important for identifying important sites for conservation and land use, such as determining knots exposure to offshore wind facilities and wind collision risks49. PubMedGoogle Scholar. This study shows a portion of knots do not use either of these regions, highlighting the need to expand the geographic regions included in these estimates. https://www.federalregister.gov/documents/2014/12/11/2014-28338/endangered-and-threatened-wildlife-and-plants-threatened-species-status-for-the-rufa-red-knot (2014). They have to fly over vast areas of unsuitable habitat like forest, and if they run out of juice, they have to either turn around or chance it until they can get to the breeding areas, he said. Stopover duration (time elapsed between first and last detection) relative to arrival date in Delaware Bay for 8 adult and 1syear red knots. As expected, knots that arrived earlier to Delaware Bay stayed longer than knots that arrived later, because Delaware Bay is the final stop for many knots before arriving in boreal andArctic habitat from late May to early June6,17. The decline in Red Knot populations has chiefly been caused by the lack of sufficient eggs for foraging birds on the Delaware Bay. Spring 2021 surveys of Delaware Bay, New Jersey USA, a crucial staging site for northward migrating red knots, produced the lowest red knot numbers since 19817. Larry Niles, an independent wildlife biologist who has trapped, monitored and counted shorebirds on the bay beaches of New Jersey for the last 25 years, said he had been expecting some decline in this years red knot count because of signs of a poor breeding season in 2020, but was shocked by the size of the drop. Documents | Delaware Riverkeeper Network Effective management of migratory species depends on a nuanced understanding of their movement pathways through space and time. 8 East Frederick Place, Cedar Knolls, New Jersey 07927, United States. With more than 80% losses in some shorebird population numbers, certain species - like the Red Knot - are now teetering on the brink of extinction. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Similarly, Ruddy Turnstones tagged in late May in South Carolina flew directly through the Great Lakes region toward boreal and Arctic habitat and none were detected on the Atlantic coast between South Carolina and New Jersey29. 4, 3. https://doi.org/10.1186/s40462-016-0067-8 (2016). All authors read and approved the final manuscript. Abstract. 6a). Linscott, J. Google Scholar. Atkinson, P. W. et al. She has studied the knot and other declining shorebirds such as ruddy turnstones and semipalmated sandpipers on the Delaware Bay since the early 1980s. Although individuals demonstrate variation in migratory routes, a recent analysis of resighting data found that knots in the Southeast United States are 75% site faithful to specific sites (within a 30km radius) from one year to the next, yet, similar to our study, they also found within-year movement between sites in South Carolina, Georgia, and Florida39. CAS As many as 30 species of shorebirds visit the Delaware Bay in May. However, there was considerable overlap in body mass among the three groups and migration strategy explained only about 10% of the variation in capture mass (Fig. Numbers of other shorebird species visiting the bay this year have also fallen sharply, said David Mizrahi, vice president for research and monitoring at New Jersey Audubon. Rep. 9, 9420. https://doi.org/10.1038/s41598-019-45862-0 (2019). This year, he also blamed predation by peregrine falcons, whose growing coastal population has been helped by the construction of nesting platforms by New Jersey. insects, green vegetation, seeds. (Motus Wildlife Tracking System, 2020) https://motus.org/wp-content/uploads/2020/02/tag_deployment_methods.pdf. Piersma, T. & Baker, A. J. Additionally, one of three knots tagged in Florida that provided migration route information flew directly to the southern Great Lakes, its final detection, from its tag deployment location in Florida. Red Knots in Steepest Decline in Years, Threatening the Species Rufa Red Knot (Calidris canutus rufa) 5-Year Review: Summary and Evaluation (New Jersey Field Office, 2021). But he says it's much too soon to declare victory. Andres, B. et al. In the late 1990s and early 2000s, the number of Red Knots found at Delaware Bay dramatically declined from ~50,000 to ~13,000. 4), and eastern Saskatchewan (not illustrated). The best hope for the species to survive lies in a complete ban on harvesting female horseshoe crabs until the crab population recovers, Dr. Niles said. People have to stop killing horseshoe crabs until they recover, Niles said. Ironically, there were plenty of crab eggs to eat on the bay beaches this year, but a long-term decline in the availability of eggs has severely dented the birds population, thinning any cushion that would enable the species to survive natural hazards. wrote the manuscript. For a better-informed future. 36, 1185 (2008). We classified a single individual to have likely stopped in Delaware Bay as it was detected multiple times over two or more days but just outside our defined watershed. Volunteers trapped shorebirds for counting and tagging at Reeds Beach in Middle Township, N.J., in 2019. Arctic nesting shorebirds make some of the longest journeys of any species on earth, flying extreme distances in the spring from wintering sites to nesting sites with limited, predictable stopover sites en route1. the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in If you're wondering, 9,000 miles is roughly the equivalent of 529 trips across the Delaware Bay between Cape May and Lewes. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. At the same time, shorebirds -- especially the endangered Red Knot -- use the Delaware Bay beaches as a food stop on their annual migration from South America to the Arctic. Latest Earthquakes | Live WebChatShare Social Media, Red Knots (Calidris canutus rufa) stop at Delaware Bay on the mid-Atlantic coast of North America during northward migration to feed on eggs of horseshoe crabs (Limulus polyphemus). This research demonstrates the usefulness of Motus for tracking the migration of red knots. Strategic expansion of the Motus network in the Americas and beyond offers substantial potential to explore and understand the full life cycle of migratory shorebirds to support informed conservation decisions. The departure date for 47 adult red knots migrating northward from coastal South Carolina that (A) stopped or likely stopped in Delaware Bay, (B) used an unknown migratory route, or (C) skipped or likely skipped Delaware Bay. Google Scholar. The number of red knots visiting Delaware Bay this spring plunged to a record low, pushing the shorebirds local population closer to extinction despite a quarter-century of efforts to save it. Rufa Red Knot - U.S. Fish and Wildlife Service Michelle Gustafson for The New York Times. Effects of Horseshoe Crab Harvest in Delaware Bay on Red Knots: Are It is noteworthy that counts of five other shorebird species in Delaware Bay also declined by 50 percent from 1998 to 2007, and that the rufa red knot's Argentina/Chile wintering Even before the latest numbers, Niles resisted any suggestion that he had saved the rufa red knot, saying only that his efforts had arrested the earlier decline, and provided a base to rebuild the population. We conducted a mark-recapture-resight investigation to estimate the passage population of Red Knots at Delaware Bay in 2022. Estimated stopover used of Delaware Bay is described in the text. The objective of the ARM framework is to manage sustainable harvest of Delaware Bay horseshoe crabs while maintaining ecosystem integrity and supporting Red Knot recovery with adequate stopover habitat for Red Knots and other migrating shorebirds. & Taylor, P. D. Differential fall migratory routes of adult and juvenile Ipswich Sparrows (Passerculus sandwichensis princeps). data). This is where you will generally find the highest concentrations of Red Knots. Body condition explains migratory performance of a long-distance migrant. Tracking movements of threatened migratory rufa Red Knots in U.S. Atlantic Outer Continental Shelf Waters, 145 (US Department of the Interior, Bureau of Ocean Energy Management, 2018). Conservationists found fewer than 7,000 of the birds rufa subspecies during extensive counts on land, air and water on the New Jersey and Delaware sides of the bay during May. To estimate the departure window from coastal South Carolina to northern destinations we used two methods. ADS Senner, N. R. et al. Dr. Niles estimated that around 40 percent of last years migrants died before they reached the Arctic, simply because they ran out of energy. The cold water delayed the spawning of horseshoe crabs until early June, by which time the birds had already left the Delaware Bay in an attempt to complete their migration. Red Knots & Horseshoe Crabs: A Delaware Bay Exclusive Red Knot (Calidris canutus), version 1.0. Delaware Bay Ecology - DNREC Alpha Scientific Reports Baker, A., Gonzalez, P., Morrison, G. & Harrington, B. 284, 20171374 (2017). [2] Six subspecies are recognised. Circle diameters reflect the number of individual birds detected by a given receiving station. As Chris Bennett of the Delaware Division of Parks and Recreation explains, "These birds have just traveled thousands of miles, expended incredible amounts of energy and in most cases have lost nearly half their body weight. Birds can be seen feeding at nearly any time during the day. Developmental Disabilities Centers - Atlantic Health Proc. NJDEP| Fish & Wildlife | Delaware Bay Shorebirds Similar to Sanders et al.29, we compared the relative use of the Atlantic Coastal route through Delaware Bay versus an inland route using patterns of tag detections in two primary watersheds: Delaware Bay, which we defined as any stations within 30km of the (HUC 02040204) Delaware Bay Hydrological Unit30, and the Great Lakes Basin as the 5 lakes and their associated subbasin watersheds31. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. government. 2008, 2010).Concurrently, a decreasing proportion of red knots stopping in Delaware Bay reached the . COSEWIC assessment and status report on the Red Knot Calidris canutus, islandica subspecies (Calidris canutus islandica), roselaari subspecies (Calidris canutus roselaari) and rufa subspecies (Calidris canutus rufa) in Canada. Spring staging sites provide food that will fuel flights toward Arctic breeding grounds46, and for survival in cold high latitude conditions upon arrival47. Red knot - Wikipedia Official websites use .gov https://doi.org/10.1098/rspb.2004.2713 (2004). . Views expressed by our advertisers and sponsors are their own, and are not endorsed by NJ Spotlight News. Life history characteristics and the conservation of migratory shorebirds. Proc. 2021. . 3). Secure .gov websites use HTTPS Conserve Wildlife Foundation of New Jersey and the Endangered and Nongame Species Program (ENSP) of . The search for food and nesting area . Delaware Bay Shorebird Conservation Project - Conserve Wildlife U.S. Fish and Wildlife Service. The Delaware Bay is the final and most critical rest stop for these migratory birds. Present address: American Bird Conservancy, The Plains, VA, 20198, USA, Present address: Thompson Rivers University, Kamloops, BC, V2C 0C8, Canada, U.S Fish and Wildlife Service, National Wildlife Refuge System, Inventory and Monitoring Branch, Athens, GA, 30605, USA, South Carolina Department of Natural Resources, 220 Santee Gun Club Road, McClellanville, SC, 29458, USA, Florida Gulf Coast University, Fort Myers, FL, 33965, USA, South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, SC, 29412, USA, U.S. 302-735-3600. Any opinions, findings, and conclusion or recommendations expressed in this material are those of the authors and do not necessarily reflect the view of the funding agencies or the U.S. If you must go onto the beaches, set up during low tide and remain as quiet and still as possible. McKellar, A. et al. Knots only stop at sites with high quality prey to speed up their migration time45. Departure dates of red knots using an unknown migratory route overlapped other departures as well, with a median date of departure of May 5 (Fig. Jon Hurdle, a freelance writer who regularly reports on water and other environmental issues, is part of the NJ Spotlight COVID-19 reporting team. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. & Skowron Volponi, M. A. trajr: An R package for characterization of animal trajectories. Species Status Assessment Report for the Rufa Red Knot (Calidris canutus rufa). This figure was created in R (version 4.1.2), available from https://www.r-project.org. The ability to gain sufficient weight during northward migration is crucial, and a shortage of food resources in Delaware Bay has been linked to reduced subsequent adult survival and reproductive success of red knots41. Although the crab harvest is banned on the New Jersey side of the bay it continues in the other bay states of Delaware, Maryland and Virginia, albeit subject to quotas set by the Atlantic States Marine Fisheries Commission. Threatened Species Status for the Rufa Red Knot. A synthetic alternative, rFC, is available, and is used by at least one pharmaceutical company, but the industry as a whole has been slow to adopt the new technique, resulting in continued demand for horseshoe crabs in the bay. Thibault, J. Assessing the Status and Use of Red Knots in South Carolina (South Carolina Department of Natural Resources, 2013). We deployed nanotags on 108 red knots. 2004; Niles et al. 77, 437472 (1996). Data collection and collation were made possible by the Motus Wildlife Tracking Network and Birds Canada. We identified stopover events for 11 adult red knots. Version 1.1 (Ecological Services New Jersey Field Office, 2020). The red knot (Calidris canutus) population wintering in Tierra del Fuego (TDF) and stopping in Delaware Bay during northward migration has declined.Knots at wintering sites in Patagonia and TDF dropped from 67,500 in the mid-1980s to 16,260 birds in 2009 (Morrison et al. (B) Relationship between estimated ground speed of red knot flights and surface tailwind at the initiation of the flight. What were trying to do is not just bring back the bird, he said. Precise departures dates from South Carolina could be calculated for only 10 adult red knots. Mackenzie, S. A. et al. Red Knot stopover population size and migration ecology at Delaware Bay, USA, 2021. This difference may be a result of our small sample size (N=9) or because knots in our study utilized Delaware Bay as a secondary stopover, after having stopped at least one other site along the U.S. Atlantic coast, rather than only stopping in Delaware Bay. Any time they are disturbed, they have to stop feeding or resting and expend much needed energy.". Even though the crabs are returned to the ocean after being bled, Niles and his associates estimate that about 30% of them die or are unable to breed after being bled. Funding for a portion of the transmitters came from the U.S. Wader Study Group Bull. The number of individuals in each category is indicated in parentheses.