Domain: Natural Science — Morphology
Target concept: Sexual dimorphism in African sunbirds: Males display bright, iridescent (metallic-sheen) plumage patches, while females display plain, non-iridescent (dull brown/olive-gray) plumage.

Video generation prompt: Two African sunbirds are displayed side by side, with the female on the left and the male on the right. Observe and compare the morphological differences between these two sunbirds.

Evaluation guide:
(i) Target concept: Visual demonstration of sexual dimorphism via presence/absence of a species-typical morphological trait (bright iridescent, metallic-sheen plumage) tied to biological sex.
Minimum mechanism: The iridescent plumage patch is a fixed, non-behavioral, anatomically anchored feature of the male's feathers (e.g., on the throat, crown, or back); its absence in females, who show plain, dull, non-iridescent plumage, is complete and developmentally invariant, with no ontogenetic overlap or environmental modulation.
(ii)Storyline: Frame opens with a stable, front-facing, full-body view of two sunbirds aligned horizontally. Left bird is motionless, uniformly dull-toned (brown, olive, or gray), with no bright or metallic-sheen feather patch anywhere on its body. Right bird is motionless, with the same posture, but shows a bright, iridescent/metallic-sheen plumage patch clearly distinct from its own surrounding duller feathers. No camera movement, no lighting transition, no occlusion: both birds' plumage remains simultaneously visible and unambiguous throughout. Perspective is frontal and orthogonal (no foreshortening), ensuring the presence/absence of iridescent plumage is legible without inference.

Manual:
Experimental Procedure
1. Display two African sunbirds side-by-side in the same static frame: female on left, male on right.
Observation of Experimental Phenomena
2. Female shows plain, dull brown or olive-gray plumage with no iridescent sheen; male shows a bright, iridescent, metallic-colored plumage patch (e.g., on throat, crown, or back) that contrasts with his own duller feathers and with the female's plumage.
Summary of Experimental Principles
3. Sexual dimorphism in African sunbirds: males display bright iridescent/metallic plumage (e.g., on the throat, crown, or back) as a secondary sexual characteristic used in courtship display, while females display plain, non-iridescent plumage.

Prompt Grounding rubric:
level_1: No two sunbirds present; or only one bird visible; or the birds are not African sunbird species (e.g., hummingbird, bee-eater, or other non-sunbird morphology); or the two birds are never shown together in the same frame (e.g., separate shots, split screen, or one bird entirely off-frame for the whole clip).
level_2: Two birds are present and shown together, but at least one of the following is wrong: (a) the left bird is not recognizable as a female African sunbird, (b) the right bird is not recognizable as a male African sunbird, (c) the left/right order is reversed (male on left, female on right), (d) one bird is significantly clipped by the frame edge or otherwise not fully visible.
level_3: Two African sunbirds are shown together in the same scene, female on the left and male on the right; both birds are fully visible and roughly centered in frame; no extraneous objects, text, or labels obstruct either bird; nothing in the visible plumage or body shape misidentifies the species or the assigned sex.
level_4: All conditions for score 3 are met, and additionally: the camera viewpoint stays fixed (no pan, zoom, or rotation) for the full clip, both birds hold a still perch posture (no sustained flight, wing-flapping, or head-turning large enough to hide the plumage being compared), and the two birds appear at comparable visual scale (neither dramatically smaller or larger due to distance or cropping).
level_5: All conditions for score 4 are met, and additionally: the left (female) bird shows plain, dull, non-iridescent plumage (brown, olive, or gray tones) with no bright metallic patch anywhere on her body, and the right (male) bird shows a clearly visible, bright, iridescent/metallic-sheen plumage patch (e.g., on throat, crown, or back) that is visually distinct from his surrounding plumage, with no ambiguity about which bird carries the bright iridescent trait, and neither bird's coloration shows unnatural hue shifts, oversaturation, or desaturation relative to real sunbird plumage.

Scientific and Causal Correctness rubric:
level_1: No sexual dimorphism in plumage is depicted; or the bright iridescent patch appears on the left bird (female) while the right bird (male) is plain (the pattern is fully reversed from biological fact); or both birds show the same plumage condition (both plain or both iridescent); or non-biological features are shown (e.g., a painted-on ornament, a missing head, or a detached feather patch floating apart from the body).
level_2: Both birds show some plumage difference and the brighter plumage correctly appears on the right bird (male), but at least one of the following is wrong: (a) the bright patch appears on an implausible body region unrelated to documented sunbird iridescence (e.g., a wing-feather tip or a leg instead of throat/crown/back); (b) the bright patch looks non-plumage-like (e.g., a flat painted stripe, a glowing outline, or a geometric shape rather than feather texture); (c) the female shows a faint but visible trace of iridescence rather than being fully plain, blurring the intended contrast.
level_3: The left bird (female) shows plain, non-iridescent plumage and the right bird (male) shows a bright iridescent/metallic patch; the patch sits on a plausible plumage region (throat, crown, or back); both birds display normal avian body structure (intact bodies, feathered surfaces, no extra limbs, fused beaks, or other anatomical errors).
level_4: All conditions for score 3 are met, and additionally: the male's iridescent patch reads as a saturated metallic hue (e.g., green, blue, violet, or coppery, not dull gray or brown) clearly brighter than his own surrounding body plumage; the female's plumage is uniformly non-iridescent across her whole body, with no bright or metallic-sheen feature anywhere.
level_5: All conditions for score 4 are met, and additionally: the bright iridescent coloration is confined to the male and entirely absent from the female (no faint sheen, no partial iridescent patch, and no crest or other fabricated ornament substituting for the plumage trait on either bird), and the rest of each bird's visible plumage is consistent with the assigned sex (female uniformly dull-toned, male showing localized iridescence rather than iridescence spread evenly over his whole body).

Spatiotemporal Consistency rubric:
level_1: Severe spatiotemporal break: one or both sunbirds vanish or appear abruptly partway through the clip; either bird's position jumps discontinuously from one side of the frame to the other; either bird's size changes abruptly with no corresponding camera move; the scene's lighting changes in a way inconsistent with a single static setup; or a bird's body is momentarily incomplete (e.g., its head or wing vanishes then reappears).
level_2: Moderate disruption: one bird briefly flickers, partially disappears, or becomes occluded by the other bird or a stray object; noticeable jitter or frame instability makes the birds appear to drift in position; the lighting on one bird visibly differs from the lighting on the other or changes across frames; or part of either bird (e.g., the male's iridescent patch or the female's tail) is clipped by the frame edge inconsistently across frames.
level_3: Both sunbirds stay continuously visible for the full clip; neither bird jumps in position or size; the male's iridescent patch and the female's plain plumage each keep the same brightness and hue from the first frame to the last, with no unexplained shift in illumination across the shot; neither bird's body appears to stretch, warp, or melt; both birds keep a stable, forward-facing perch orientation with no unnatural spinning or flipping.
level_4: All conditions for score 3 are met, and additionally: the female stays on the left and the male stays on the right at the same apparent depth throughout, with no parallax shift suggesting either bird is moving toward or away from the camera; motion blur never obscures the male's iridescent patch or the female's plain plumage; and the clip shows no frozen-frame stutter or repeated duplicated frames.
level_5: All conditions for score 4 are met, and additionally: any small naturalistic movements the birds make while holding their perch (such as a slow blink, a slight feather ruffle, or a small head turn) stay subtle enough that a viewer can still clearly compare the two birds' plumage at every moment, with no visible flicker, no popping in and out of feather detail, and no brightness fluctuation across frames that would make the male's iridescent patch or the female's plain plumage momentarily hard to judge by eye.