Great Egret

Diagnostic Feature Combination

Require mutually supporting views of proportions, bill, feet and plumage, retaining obscured features as unknown.

1. Which visible features support Great Egret, and which plausible local white herons remain unexcluded? boundary
2. What original photographs, field notes or expert review support the identification? provenance

Bare Part Variation

Bill and leg colours vary among regional breeding forms, so a yellow-bill rule cannot apply universally. [Cornell identification](https://www.allaboutbirds.org/guide/great_egret/id)

1. Which regional and breeding-state comparison applies to this bird's bill, lores and legs? definition
2. Which taxonomic authority defines the Great Egret concept used for this observation? provenance

Accessible Feeding Water

Great Egrets commonly hunt in shallow fresh, brackish or marine water using waiting and wading behaviour. [Cornell life history](https://www.allaboutbirds.org/guide/great_egret/lifehistory)

1. What water depth, substrate and vegetation surround the bird's actual feeding position? measurement
2. Does observed water-level change expose feeding shallows or prevent the bird from using them? boundary

Observed Feeding Success

Record prey evidence and timed attempts without inferring diet or nutritional condition from one encounter.

1. During what observation interval were strikes, captures and successful swallowing actually visible? measurement
2. What evidence identifies the captured prey, and at what taxonomic resolution? provenance

Active Nest Evidence

Great Egrets nest colonially, including alongside other waterbirds; nest ownership therefore needs direct evidence. [Australian Museum](https://australian.museum/learn/animals/birds/great-egret/)

1. What repeated attendance or reproductive behaviour links this Great Egret to this particular nest? provenance
2. Is the observation evidence of nesting, courtship or only communal roosting? boundary

Breeding Outcome Confidence

Keep observed eggs, chicks and fledging separate from inferred losses when nest visibility changes.

1. How many eggs or young were visible on each date, and how complete was the view? measurement
2. What evidence distinguishes fledging, temporary concealment and mortality when a chick is no longer seen? boundary

Defensible Reidentification

Use readable marks or documented tracking evidence; leave unmarked sightings unlinked when continuity is uncertain.

1. Which ring inscription, tag or persistent feature supports recognising this individual again? provenance
2. Could these records represent different Great Egrets or a duplicate count? boundary

Site Dependence Evidence

Record the frequency and purpose of visits while separating missed detection from absence.

1. Across what dates and observation effort has feeding, roosting or breeding use been recorded? measurement
2. What evidence supports residence, passage or movement between a roost and feeding area? provenance

Impairment Versus Normal Behaviour

Record asymmetry, visible entanglement and failed movements alongside life stage and observation duration.

1. What directly observed difficulty affects standing, walking, flight, prey capture or swallowing? measurement
2. What evidence warrants wildlife-responder referral rather than continued distant observation? action

Permissible Next Action

Make approach, handling and site-work decisions conditional on observed effects and applicable local requirements.

1. Has observer or equipment proximity interrupted feeding, displaced the bird or altered nest attendance? measurement
2. What current authority, qualifications and site-specific restrictions govern the proposed approach, capture or intervention? action

Kinds and varieties

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

1. Which of these kinds and varieties hold for the sense of Great Egret this model covers, and on what evidence? provenance

Identifiers and schemes

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

1. Which of these identifiers and schemes hold for the sense of Great Egret this model covers, and on what evidence? provenance

Standards and regulation

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

1. Which of these standards and regulation hold for the sense of Great Egret this model covers, and on what evidence? provenance

Real-world use

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

1. Which of these real-world use hold for the sense of Great Egret this model covers, and on what evidence? provenance

Typical measurements

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

1. Which of these typical measurements hold for the sense of Great Egret this model covers, and on what evidence? provenance

Failure modes and hazards

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

1. Which of these failure modes and hazards hold for the sense of Great Egret this model covers, and on what evidence? provenance

Regional variation

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

1. Which of these regional variation hold for the sense of Great Egret this model covers, and on what evidence? provenance

Neighbouring kinds and how to tell them apart

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

1. Which of these neighbouring kinds and how to tell them apart hold for the sense of Great Egret this model covers, and on what evidence? provenance