Disruptions in the Flyway: Sharing our resources with the Red Knots

 Faye Gilbert

Prof. John Horgan - HST401

 January 29^th, 2026       

 

Disruptions in the Flyway: Sharing our resources with the Red Knots  

The word “flyway” reads somewhat poetically. Even to one unaware of its meaning, it could be gathered from the liquid consonants and the continuity that the letter “y” drives softly forward. I can only imagine it was chosen representatively by the 19^th century journalists who coined it, even subconsciously. 

                  It’s May. The Red Knot, a small, stocky, yellow-bellied shorebird is mid-migration and makes it typical stop in its flyway at the Delaware Bay, just as it did last year and the year before. It arrives hungry, and it searches the shoreline for the abundance of excess horseshoe crab eggs it found so conveniently strewn about last year’s beach. The horseshoe crabs are careless, or maybe forgetful. The eggs they so carefully laid and buried just nights ago are doomed to this fate: dug right back up to make room for the next set. 

                  Only this year, to the shorebirds surprise, the eggs are gone. They are safely tucked beneath the beach apart from a few stragglers, so few that their presence is more taunting than it is a meal. Where have the eggs gone? Are they, perhaps, just further down the beach? Is it a cruel trick of wind, and are they right at the bird’s feet under a deceiving layer of sand? Could the horseshoe crabs have grown less careless? Less forgetful? 

                  It’s not the horseshoe crabs that have changed their ways, but us. We are responsible for the dwindling of the horseshoe crab population, and for that of its eggs. In part, a few likely unaware, but not innocent, fishermen have found them to be nice bait. The decline is most attributable, however, to biomedical use. 

                  The blood of a Horseshoe crab contains proteins called amebocytes that protect against infection. Specifically, it is protective against endotoxin, a type of pyrogen and part of the cell wall of gram-negative bacteria such as E. coli. Frederik Bang began this discovery in 1953 during his research at John Hopkins. He spent a summer studying the already known coagulation, or the changing from a liquid to a semi-solid, that occurs when horseshoe crab blood came in contact with certain bacteria. He and a colleague Jack Levin, a decade later, solidified the finding that the coagulation process was especially strong in presence of endotoxins. They developed the Limulus amebocyte lysate (LAL) Test, which applied this discovery to pharmaceutical research. If endotoxins enter the human blood stream, it can lead to sickness or death. This application has been revolutionary in that it replaced the earlier method of testing for endotoxins in the ingredients and containers of vaccinations and injectables, which involved a 4-6 hour wait time and the possible death of an innocent rabbit. Idealistically, horseshoe crabs can be released back into the ocean unscathed after the drawing of blood. However, that isn’t always the case. The survival rate of returned crabs is only 85-90%, which has taken a hit to the overall population.

Clearly, though, the use of horseshoe crab blood is not only beneficial, but crucial to modern medicine and public health, so what’s the issue? Can’t the population take a small hit? Can’t the Red Knots, the sandpipers, the dowitchers, and the sanderlings spare a few meals for our sake? The issue isn’t that we are sharing in the bird’s resources, it’s that we are taking more than we should, and need, for that matter. We often overharvest horseshoe crab blood rather than taking just what we need.

Horseshoe crab eggs are a crucial aspect in the diet and survival of all shorebirds, but specifically of the Red Knot. The Red Knot’s label as endangered in New Jersey is due to the decline of these eggs. While we protect endangered species, in part, for the sentiment, just as we protect ourselves, that is far not the only reason. Like most wonders in nature, their roles often go unnoticed. The flyway of the migrant shorebirds that feed on them spans 15,000 miles annually between their arctic breeding grounds and stops in the South. This means these birds have a prominent role in the flow of energy and resources between different biomes and climate zones. Their health and well-bring reflects that of wetlands and coastal overall. 

There is no doubt that there is an overwhelming need for horseshoe crabs, but there is no doubt that the need is shared. We wouldn’t want something to vital to our health and survival taken from us, so it’s important that we find to share the resources between ourselves and the birds.  

 

Works Cited

» Biomedical Use of Horseshoe Crabs | the Horseshoe Crab. horseshoecrab.org/biomedical-use-of-horseshoe-crabs/.

Charles, Ritcher. “Blue Bloods.” American Association of Immunologists, 2022, www.aai.org/About/History/History-Articles-Keep-for-Hierarchy/Blue-Bloods-Bang,-Levin,-and-the-Horseshoe-Crabs.

Piersma, Theunis, and Åke Lindström. “Migrating Shorebirds as Integrative Sentinels of Global Environmental Change.” Ibis, vol. 146, 23 Sept. 2004, pp. 61–69, https://doi.org/10.1111/j.1474-919x.2004.00329.x.

Nj.gov, 2025, dep.nj.gov/dsr/environmental-trends/wildlife-populations-red-knot/.