Nature - USA (2020-01-23)

Life sciences study design

All studies must disclose on these points even when the disclosure is negative.

Sample size For each animal all available data ¡n the given developmental window of interest was chosen.

Data exclus¡ons Out of a set of L6 animals, Ll- were excluded because recording conditions were inadvertently changed mid-experiment by modifyìng the

amplifier settings.

Replication We did not attempt replication using a different dataset.

Randomization nla

Blinding Des< nbe whetl¡er the ¡nvestigotots wpt? bl¡nded !o q,oup ottoco¡ion Curtnq doto colleç¡¡6n nnd/ot onotysis. lf bttndtnq Áos not po\s¡ble.

describe why OR exploin why blinding was not relevant to your study.

Reporting for specific materials, systems and methods

We requ¡re information from authors about some types of materials, experimentalsystems and methods used in many studies, Here, ìndlcate whether each material,

system or method listed is relevant to your study. lf you are not sure if a list item applies to your research, read the appropriate section before selecting a response.

Materials & experimental systems Methods

lnvolved in the study n/a lnvolved in the study

! Antibodies I chtr-seq

n

T

X

I

u

n/a

X X X T X X

Eukaryotic cell lines

Palaeontology

Animals and other organisms

Human research part¡cipants

Clinical data

Xfl Flow cytometry

I vRt-based neuroimagìng

Animals and other organisms

Policy information about studies involvine animals: ARRIVE suìdelines recommended for reporting animal research

Laboratory animals Zebra Fìnches, Male

Wild animals Provide detoils on onimals obserued in or captLtre(l ìn the field; report spec¡es, sex and age where possble. Describe how antmols

were caught and tronsported ond what hoppened to captive an¡mals after the study {if killed. exploín why and describe method; if

releosed, say where ond when) OR stote thot the stLtdy did not ¡nvolve wild onimals.

Fìeld--collected samples For loborotory work with field-collecled somples, describe all relevant porometers such as housing, md¡ntenance. temperoture,

photoperiod ond end Õf exper¡ment protocol OR slote that the study d¡d not involve samples collected from the field.

Eth ics ove rsight Al I experimental procedures were a pproved by the Veterinary Office of the Ca nton of Zurich.

Note that full informatìon on the approval ofthe study protocol must also be provided in the manuscript.