Assertion: billed gull | /r/HasProperty | its black bill
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text: Easily mistaken for the red-billed gull, the black-billed gull is distinguished by its black bill and is described as having a “more delicate appearance,” a “more buoyant and graceful” flight, and being “generally less noisy,” despite having a similar call.:546 F1 and F2 hybrids between the two gulls have been observed, both hybrids exhibiting dark red bills.:556