Goofs

After Mary Poppins powders her nose black, her face in the next scene is clean again.

When Mary Poppins is tidying the nursery, the pictures straighten, but in the next shot, they are still crooked.

Mr. Banks tears Jane and Michael's advertisement into eight pieces. Only eight pieces of paper float up the chimney, but at least twice as many are shown coming out of the top of the chimney.

When Bert traces Mary's shadow on the sidewalk, the sunlight obviously comes from behind Mary. However, when Bert stands up to greet Mary, the sun shines frontally into her face.

When the penguins bring Mary and Bert menus, the menus are pink. A moment later, Bert's menu is bright purple.

When Mr Banks takes the children to the bank, we hear the song Fidelity Fiduciary Bank. Banks don't have pointlessly hyperbolic names like this in England. Only American banks use such names.

It has been asserted that the robins on the nest outside the nursery are both male. The one on the right is somewhat paler than the other one, indicating a female. The difference between sexes in robins is slight compared with many other birds, and these are in reasonably good agreement with the robins shown in Roger Tory Peterson's "Eastern Birds".

Mary's glove appears to darken in the closeup when she reads the advertisement to Mr. Banks due to the lighting.

In the penguin number Dick Van Dyke's pants change to short legs and long crutch to long legs and short crutch. This was deliberate, as Bert is clearly seen adjusting his trousers to match the shape/characteristics of the penguins he is dancing with just prior to and following the scene.

At the end, the Constable described the "missing" Mr. Banks as "about 6 foot 1 inch. There is a common misconception outside of Europe that Britain only uses the metric system when, in fact, they use both. Britain didn't begin using the metric system until the early 1970s. Imperial measurement (slightly different to American) is still used almost exclusively for measuring people/clothing and for road speeds/distances.

The scene at night in the children's bedroom is incredibly bright. That type of lighting did not exist in homes, especially bedrooms, in 1910.

However, as the film also involves a magical nanny and dancing cartoon penguins, it should be assumed that this was the production team deliberately using artistic licence rather than making an anachronistic error.

When the Constable brings the children home after Katie Nanna quits, Michael tries explaining why they ran off. While he is saying, "It was windy out," Jane can be seen mouthing that line while Michael is saying it.

Obvious stand-ins for Mary, Bert, Jane, and Michael when Mary Poppins, Bert, and the children step onto a cloud which wafts them back down after exploring the rooftops (just before the "Step in Time" number).

During the "Step in Time" number when the chimney sweeps pop out of the chimneys, in one scene all three sweeps are seen coming up behind the chimneys and not out of them.

When Mary and Bert are dancing with the cartoon penguins, Bert's legs and some of the "real" scenery can be seen through the cartoon penguins in some shots.

During the beginning of the "I Love to Laugh" sequence, when Uncle Albert says, "Loud and long and clear", his left hand goes transparent into the background. (From the 40th Anniversary Edition)

When the Banks family are vacating their empty house, 13A power sockets of a type not in wide use until the 1960s can be seen.

When Mr. Banks is dismissed from the bank, he takes Michael's two pennies from his pocket and these are seen as King Edward VII pennies, which are correct for the period. However the coins are worn and battered, as if they had been in circulation for decades, whereas the longest an Edward VII coin could possibly have been in circulation in 1910 would have been eight years; as such the coins should have looked nearly (if not actually) new.

In the aerial scene in the opening, Westminster Cathedral, which is located just east of Westminster Abbey, does not exist. Since it was completed in 1903, seven years before the film takes place, it should be present.

When Mr. Dawes, Sr. comes out to see Mr. Banks, Jane, and Michael, he's talking, but his mouth doesn't move.

When Michael is locked in the closet while cleaning the nursery, the door opens for several seconds, and he is heard to yell "Let me out!" repeatedly, but his mouth doesn't move.

When Bert is singing one of his comical poems, a harmonica tune can be heard; however it's visible, but Bert himself doesn't always play it.

At the end of his opening song, Bert hits himself on the head with a cymbal. He is holding it with two hands but a cymbal touched on the rim will muffle and not sound clear and long.

When Mary Poppins, Jane, and Michael are sliding down the stairs' handrail as they pass in front of Ellen, part of the trolley is visible on Michael's left.

During the "I Love to Laugh" sequence, the strings attached to Michael are visible in front of Mary's face when he first takes off. Later, the strings lifting Mary are visible when she joins the others at the table - showing that they are attached to her at the waist, just below her pocket.

When Bert first walks onto Cherry Tree Lane and the camera follows him, the shadows of equipment are visible on the lamp post in the foreground.

When Mary first turns from the window with the robin perched on her fingers, the cables operating the bird are visible on the back of her hand.

When the four carousel horses are lined up, Dick Van Dyke's cable can be seen.

The robin that lands on Mary's finger in the "Spoonful of Sugar" sequence is an American robin (Turdus migratorius), not a British robin (Erithacus rubecula).

When Mary Poppins and the children supposedly go shopping before their unexpected visit with Uncle Albert, they are told by Admiral Boom to "proceed at Flank speed". A Royal Navy officer would have used "Full" speed as "Flank" is only used by the United States Navy to indicate a speed between "Full" and "Emergency".

In the opening title montage image, St Paul's Cathedral is shown to be between Tower Hill and Westminster, whereas it is in the opposite direction.

When the children run out of the bank, which is close to St. Paul's Cathedral, they immediately find themselves in the slums of the East End. In fact, the East End is well over a mile from St. Paul's.

When Mrs. Banks bends to embrace the children (when the Constable brings the children back from the park), her head is turned to her left rather than looking at her children, obviously anticipating Mr. Banks' line which cuts off her embrace.

The American production can be evidenced by Mr. Banks pronouncing the word niche as "nitch" towards the end. In England the word is pronounced "neesh".

When Mary Poppins says the word "supercalifragilisticexpialidocious" backwards, she pronounces the final two syllables ("repus") 'ROO-pus' rather than 'REE-pus' or 'REPP-us'.

After all the chimney sweeps leave the house, Jane tells her father that every one of them shook his hand. In fact, this isn't true. A big handful of them simply had tipped their hats to him on their way out.

Reta Shaw, as Mrs. Brill the cook, is one or two of the American actors in the film who doesn't attempt to use a British accent, although the cook should have spoken with a British accent to make the film more authentic.