A case report of biochemistry and serum amyloid A in a moribund free-ranging Baltic herring gull (Larus argentatus) with necrotic wing fracture

An adult herring gull (Larus argentatus) found lethargic and moribund showed an open fracture of the right radius and ulna with necrosis of the surrounding tissue. Hematologic testing and plasma biochemical analysis revealed elevated creatinine kinase consistent with traumatic muscle damage in addition to hyperuricemia, hyperkalaemia, and hyperphosphatemia consistent with renal insufficiency. Increase in the acute phase protein Serum Amyloid A indicate a high degree of inflammation supported by leucocytosis, heterophilia, and hypoglycaemia pointing towards septicaemia. This case provides knowledge about Serum Amyloid A in gulls, and how bone fracture and secondary infection may affect gull blood haematology and biochemistry.

Nest sanitation behavior does not increase the likelihood of parasitic egg rejection in herring gulls

Birds’ behavioral response to brood parasitism can be influenced not only by evolution but also by context and individual experience. This could include nest sanitation, in which birds remove debris from their nests. Ultimately, nest sanitation behavior might be an evolutionary precursor to the rejection of parasitic eggs. Proximately, the context or experience of performing nest sanitation behavior might increase the detection or prime the removal of parasitic eggs, but evidence to date is limited. We tested incubation-stage nests of herring gulls Larus argentatus to ask whether nest sanitation increased parasitic egg rejection. In an initial set of 160 single-object experiments, small, red, blocky objects were usually rejected (18 of 20 nests), whereas life-sized, 3 D-printed herring gull eggs were not rejected whether red (0 of 20) or the olive-tan base color of herring gull eggs (0 of 20). Next, we simultaneously presented a red, 3 D-printed gull egg and a small, red block. These nests exhibited frequent nest sanitation (small, red block removed at 40 of 48 nests), but egg rejection remained uncommon (5 of those 40) and not significantly different from control nests (5 of 49) which received the parasitic egg but not the priming object. Thus, performance of nest sanitation did not shape individuals’ responses to parasitism. Interestingly, parents were more likely to reject the parasitic egg when they were present as we approached the nest to add the experimental objects. Depending on the underlying mechanism, this could also be a case of experience creating variation in responses to parasitism.