Domain: Natural Science — Morphology
Target concept: Reverse sexual dimorphism in the woodpecker: females possess red crown feathers, whereas red crowns are typically found in males.

Video generation prompt: Mark the sex of two woodpeckers. Use a pointing rod to indicate the color and morphological differences in the red crown feathers between males and females.

Evaluation guide:
(i) Target concept: Visual identification of sex via crown color dimorphism in woodpeckers.
Minimum mechanism: Two conspecific woodpeckers must be co-present, statically posed, with crowns fully visible and lit to resolve spectral differences; rod must physically contact crown to establish referential link; color perception must support red vs. non-red discrimination without metamerism or display gamut failure.
(ii)Storyline: [Frame 0–2] Stable wide shot reveals two woodpeckers side-by-side, heads upright, crowns fully in view. [Frame 3–4] Pointing rod enters frame from bottom, moves upward. [Frame 5–6] Rod tip contacts crown of left woodpecker: red color fully visible. [Frame 7–8] Rod tip lifts *without leaving frame*, moves laterally, contacts crown of right woodpecker: non-red color fully visible. [Frame 9–10] Rod remains in contact with second crown; both crowns stay in focus, unoccluded, and color-stable until end. Perspective: fixed frontal/slightly elevated viewpoint; no camera motion; no cutaways; all events occur within single continuous take.

Manual:
Experimental Procedure
1. Place two live woodpeckers side-by-side in natural lighting.
2. Use a thin, neutral-colored pointing rod to touch the crown region of the first woodpecker, then the second.
Observation of Experimental Phenomena
One woodpecker exhibits a fully red crown; the other exhibits a non-red (black/brown/gray) crown — no red pigment visible on the latter.
Summary of Experimental Principles
This species shows reverse sexual dimorphism: unlike most woodpeckers, where the red crown marks males, here the red crown marks the female, while the male shows the non-red (black/brown/gray) crown.

Prompt Grounding rubric:
level_1: No two woodpeckers appear together in the frame (e.g., only one bird, or a single bird shown twice across a cut); or no pointing rod is ever visible; or neither bird's crown is ever shown; or the two woodpeckers are positioned one behind the other or diagonally rather than beside each other, so their crowns can't be compared in the same glance.
level_2: Two woodpeckers are shown beside each other, but the pointing rod never appears; or the rod appears but never touches either bird's crown; or the rod touches a crown but it is unclear which of the two birds is being indicated; or a crown is present but hidden by feathers, shadow, or the frame edge so its color can't be judged.
level_3: Two woodpeckers are shown beside each other; the pointing rod touches the crown of each bird in turn (or touches both at once); each bird's crown is plainly visible enough to judge its color; a viewer can tell, from the rod's position alone, which bird is being indicated at each moment, with no on-screen text or narration required.
level_4: Everything required at the 3-point level, plus: the rod stays in contact with a crown for the whole time it indicates that bird rather than tapping and lifting away repeatedly; the two woodpeckers stay in the same shot throughout, with no cut or re-framing between the two indications; the rod visibly moves from the first bird's crown to the second's (or holds both at once), so the labeling order is unambiguous; both birds show a woodpecker-typical head shape and chisel-like bill, with no oversized eyes, bare/featherless skin, or other non-avian features.
level_5: Everything required at the 4-point level, plus: the rod only ever touches the crown itself (never the nape, back, or cheek) of either bird; both woodpeckers face the camera closely enough that the whole crown is exposed and unobstructed; no hand, extra tool, or on-screen label enters the shot to block the view of either crown or confuse which bird the rod is touching.

Scientific and Causal Correctness rubric:
level_1: The two woodpeckers' crowns look the same (both red, or both black/brown/gray), so no color contrast is visible between them; or neither crown shows any red at all; or the video indicates (through an on-screen label, voiceover, or unambiguous cue) that the red-crowned bird is male and the non-red one is female, which is backwards for this species' reverse dimorphism.
level_2: One crown is red and the other is not, but the non-red crown reads as an unlikely color for this species (e.g., white, yellow, or an odd blotchy pattern) rather than a plausible black, brown, or gray; or a faint red tinge appears on both crowns, blurring the contrast; or the color difference between the two crowns is so washed out or overexposed that a viewer could not confidently call one red and the other not.
level_3: One woodpecker's crown is a clear, solid red and the other's is a clear, solid non-red (black, brown, or gray); this matches the reverse dimorphism at stake here: the red crown marking the female, the non-red crown marking the male; the contrast between the two crowns is easy to see and is not faded or blown out.
level_4: Everything required at the 3-point level, plus: the red coloring stays confined to the crown itself on that bird, without spreading onto the forehead, nape, or cheek; the non-red crown is an even, single tone with no red flecks or patches breaking it up; no third crown color or additional bird appears anywhere in the shot to muddy the two-way contrast.
level_5: Everything required at the 4-point level, plus: the red crown reads as vivid and clearly separated in hue from the surrounding darker plumage, without gradually blending into it at the edges; the non-red crown shows no red tint at any point, even as lighting shifts; both crowns keep this same coloring for the entire clip, with neither one switching color partway through.

Spatiotemporal Consistency rubric:
level_1: Either woodpecker's position jumps abruptly between frames rather than staying put; or the rod appears or disappears from one frame to the next with no visible motion carrying it in or out; or the ambient lighting suddenly flashes or dims, or the cast shadows jump to a new direction with no camera movement to explain it; or a bird's head snaps past a right angle while the rod is still touching its crown, breaking the connection between rod and bird.
level_2: The rod touches a crown, lifts away, and re-touches the same crown more than once without a clear pause or re-aim in between; or the two birds' positions relative to each other drift over the course of the clip; or background elements shift independently of the birds (mismatched parallax); or a crown flickers in and out of view frame-to-frame as if glitching.
level_3: Both woodpeckers hold their relative positions and orientation throughout; the rod moves in smoothly, touches the first bird's crown, then the second's (or both together), without vanishing behind a head or wing mid-motion; there is no sudden jump in zoom level; nothing tears or ghosts between frames in a way that breaks the connection between rod and crown.
level_4: Everything required at the 3-point level, plus: the rod keeps a steady thickness and solidity as it moves rather than thinning, thickening, or becoming see-through; nothing (a feather, a branch, or the other bird) passes between the rod tip and the crown while they are in contact; both birds hold a steady, non-blurred pose during each indication, so the boundary between the red and non-red crown stays sharp rather than smeared by motion blur.
level_5: Everything required at the 4-point level, plus: the rod's path from one crown to the other is smooth and continues in one direction, without stalling, trembling, or reversing; both birds keep their gaze toward the camera throughout, without darting away during an indication; no frame repeats, skips, or stutters that disrupt the rod's movement or the visibility of either crown.